Add libc++ and libc++abi to third-party.

third_party/libcxx/include/algorithm

+// -*- C++ -*-
+//===-------------------------- algorithm ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ALGORITHM
+#define _LIBCPP_ALGORITHM
+
+/*
+    algorithm synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+template <class InputIterator, class Predicate>
+    bool
+    all_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Predicate>
+    bool
+    any_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Predicate>
+    bool
+    none_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Function>
+    Function
+    for_each(InputIterator first, InputIterator last, Function f);
+
+template <class InputIterator, class T>
+    InputIterator
+    find(InputIterator first, InputIterator last, const T& value);
+
+template <class InputIterator, class Predicate>
+    InputIterator
+    find_if(InputIterator first, InputIterator last, Predicate pred);
+
+template<class InputIterator, class Predicate>
+    InputIterator
+    find_if_not(InputIterator first, InputIterator last, Predicate pred);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    ForwardIterator1
+    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
+             ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    ForwardIterator1
+    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
+             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    ForwardIterator1
+    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
+                  ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    ForwardIterator1
+    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
+                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator>
+    ForwardIterator
+    adjacent_find(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class BinaryPredicate>
+    ForwardIterator
+    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
+
+template <class InputIterator, class T>
+    typename iterator_traits<InputIterator>::difference_type
+    count(InputIterator first, InputIterator last, const T& value);
+
+template <class InputIterator, class Predicate>
+    typename iterator_traits<InputIterator>::difference_type
+    count_if(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator1, class InputIterator2>
+    pair<InputIterator1, InputIterator2>
+    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
+
+template <class InputIterator1, class InputIterator2>
+    pair<InputIterator1, InputIterator2>
+    mismatch(InputIterator1 first1, InputIterator1 last1, 
+             InputIterator2 first2, InputIterator2 last2); // **C++14**
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    pair<InputIterator1, InputIterator2>
+    mismatch(InputIterator1 first1, InputIterator1 last1,
+             InputIterator2 first2, BinaryPredicate pred);
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    pair<InputIterator1, InputIterator2>
+    mismatch(InputIterator1 first1, InputIterator1 last1,
+             InputIterator2 first2, InputIterator2 last2,
+             BinaryPredicate pred); // **C++14**
+
+template <class InputIterator1, class InputIterator2>
+    bool
+    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
+
+template <class InputIterator1, class InputIterator2>
+    bool
+    equal(InputIterator1 first1, InputIterator1 last1, 
+          InputIterator2 first2, InputIterator2 last2); // **C++14**
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    bool
+    equal(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, BinaryPredicate pred);
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    bool
+    equal(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2,
+          BinaryPredicate pred); // **C++14**
+
+template<class ForwardIterator1, class ForwardIterator2>
+    bool
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2);
+
+template<class ForwardIterator1, class ForwardIterator2>
+    bool
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
+
+template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    bool
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, BinaryPredicate pred);
+
+template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    bool
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, ForwardIterator2 last2,
+                   BinaryPredicate pred);  // **C++14**
+
+template <class ForwardIterator1, class ForwardIterator2>
+    ForwardIterator1
+    search(ForwardIterator1 first1, ForwardIterator1 last1,
+           ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    ForwardIterator1
+    search(ForwardIterator1 first1, ForwardIterator1 last1,
+           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator, class Size, class T>
+    ForwardIterator
+    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
+
+template <class ForwardIterator, class Size, class T, class BinaryPredicate>
+    ForwardIterator
+    search_n(ForwardIterator first, ForwardIterator last,
+             Size count, const T& value, BinaryPredicate pred);
+
+template <class InputIterator, class OutputIterator>
+    OutputIterator
+    copy(InputIterator first, InputIterator last, OutputIterator result);
+
+template<class InputIterator, class OutputIterator, class Predicate>
+    OutputIterator
+    copy_if(InputIterator first, InputIterator last,
+            OutputIterator result, Predicate pred);
+
+template<class InputIterator, class Size, class OutputIterator>
+    OutputIterator
+    copy_n(InputIterator first, Size n, OutputIterator result);
+
+template <class BidirectionalIterator1, class BidirectionalIterator2>
+    BidirectionalIterator2
+    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
+                  BidirectionalIterator2 result);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    ForwardIterator2
+    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    void
+    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
+
+template <class InputIterator, class OutputIterator, class UnaryOperation>
+    OutputIterator
+    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
+    OutputIterator
+    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
+              OutputIterator result, BinaryOperation binary_op);
+
+template <class ForwardIterator, class T>
+    void
+    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
+
+template <class ForwardIterator, class Predicate, class T>
+    void
+    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
+
+template <class InputIterator, class OutputIterator, class T>
+    OutputIterator
+    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
+                 const T& old_value, const T& new_value);
+
+template <class InputIterator, class OutputIterator, class Predicate, class T>
+    OutputIterator
+    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
+
+template <class ForwardIterator, class T>
+    void
+    fill(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class OutputIterator, class Size, class T>
+    OutputIterator
+    fill_n(OutputIterator first, Size n, const T& value);
+
+template <class ForwardIterator, class Generator>
+    void
+    generate(ForwardIterator first, ForwardIterator last, Generator gen);
+
+template <class OutputIterator, class Size, class Generator>
+    OutputIterator
+    generate_n(OutputIterator first, Size n, Generator gen);
+
+template <class ForwardIterator, class T>
+    ForwardIterator
+    remove(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class Predicate>
+    ForwardIterator
+    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class InputIterator, class OutputIterator, class T>
+    OutputIterator
+    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
+
+template <class InputIterator, class OutputIterator, class Predicate>
+    OutputIterator
+    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
+
+template <class ForwardIterator>
+    ForwardIterator
+    unique(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class BinaryPredicate>
+    ForwardIterator
+    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
+
+template <class InputIterator, class OutputIterator>
+    OutputIterator
+    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
+
+template <class InputIterator, class OutputIterator, class BinaryPredicate>
+    OutputIterator
+    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
+
+template <class BidirectionalIterator>
+    void
+    reverse(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class OutputIterator>
+    OutputIterator
+    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
+
+template <class ForwardIterator>
+    ForwardIterator
+    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
+
+template <class ForwardIterator, class OutputIterator>
+    OutputIterator
+    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
+
+template <class RandomAccessIterator>
+    void
+    random_shuffle(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class RandomNumberGenerator>
+    void
+    random_shuffle(RandomAccessIterator first, RandomAccessIterator last, RandomNumberGenerator& rand);
+
+template<class RandomAccessIterator, class UniformRandomNumberGenerator>
+    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
+                 UniformRandomNumberGenerator&& g);
+
+template <class InputIterator, class Predicate>
+    bool
+    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
+
+template <class ForwardIterator, class Predicate>
+    ForwardIterator
+    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class InputIterator, class OutputIterator1,
+          class OutputIterator2, class Predicate>
+    pair<OutputIterator1, OutputIterator2>
+    partition_copy(InputIterator first, InputIterator last,
+                   OutputIterator1 out_true, OutputIterator2 out_false,
+                   Predicate pred);
+
+template <class ForwardIterator, class Predicate>
+    ForwardIterator
+    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template<class ForwardIterator, class Predicate>
+    ForwardIterator
+    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class ForwardIterator>
+    bool
+    is_sorted(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    bool
+    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template<class ForwardIterator>
+    ForwardIterator
+    is_sorted_until(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    ForwardIterator
+    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    sort(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
+
+template <class InputIterator, class RandomAccessIterator>
+    RandomAccessIterator
+    partial_sort_copy(InputIterator first, InputIterator last,
+                      RandomAccessIterator result_first, RandomAccessIterator result_last);
+
+template <class InputIterator, class RandomAccessIterator, class Compare>
+    RandomAccessIterator
+    partial_sort_copy(InputIterator first, InputIterator last,
+                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
+
+template <class ForwardIterator, class T>
+    ForwardIterator
+    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    ForwardIterator
+    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    ForwardIterator
+    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    ForwardIterator
+    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    pair<ForwardIterator, ForwardIterator>
+    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    pair<ForwardIterator, ForwardIterator>
+    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    bool
+    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    bool
+    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    OutputIterator
+    merge(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    OutputIterator
+    merge(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class BidirectionalIterator>
+    void
+    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    void
+    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
+
+template <class InputIterator1, class InputIterator2>
+    bool
+    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
+
+template <class InputIterator1, class InputIterator2, class Compare>
+    bool
+    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    OutputIterator
+    set_union(InputIterator1 first1, InputIterator1 last1,
+              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    OutputIterator
+    set_union(InputIterator1 first1, InputIterator1 last1,
+              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    OutputIterator
+    set_intersection(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    OutputIterator
+    set_intersection(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    OutputIterator
+    set_difference(InputIterator1 first1, InputIterator1 last1,
+                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    OutputIterator
+    set_difference(InputIterator1 first1, InputIterator1 last1,
+                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    OutputIterator
+    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
+                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    OutputIterator
+    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
+                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    push_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    make_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    bool
+    is_heap(RandomAccessIterator first, RandomAccessiterator last);
+
+template <class RandomAccessIterator, class Compare>
+    bool
+    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    RandomAccessIterator
+    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
+
+template <class RandomAccessIterator, class Compare>
+    RandomAccessIterator
+    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
+
+template <class ForwardIterator>
+    ForwardIterator
+    min_element(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    ForwardIterator
+    min_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class T>
+    const T&
+    min(const T& a, const T& b);
+
+template <class T, class Compare>
+    const T&
+    min(const T& a, const T& b, Compare comp);
+
+template<class T>
+    T
+    min(initializer_list<T> t);
+
+template<class T, class Compare>
+    T
+    min(initializer_list<T> t, Compare comp);
+
+template <class ForwardIterator>
+    ForwardIterator
+    max_element(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    ForwardIterator
+    max_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class T>
+    const T&
+    max(const T& a, const T& b);
+
+template <class T, class Compare>
+    const T&
+    max(const T& a, const T& b, Compare comp);
+
+template<class T>
+    T
+    max(initializer_list<T> t);
+
+template<class T, class Compare>
+    T
+    max(initializer_list<T> t, Compare comp);
+
+template<class ForwardIterator>
+    pair<ForwardIterator, ForwardIterator>
+    minmax_element(ForwardIterator first, ForwardIterator last);
+
+template<class ForwardIterator, class Compare>
+    pair<ForwardIterator, ForwardIterator>
+    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template<class T>
+    pair<const T&, const T&>
+    minmax(const T& a, const T& b);
+
+template<class T, class Compare>
+    pair<const T&, const T&>
+    minmax(const T& a, const T& b, Compare comp);
+
+template<class T>
+    pair<T, T>
+    minmax(initializer_list<T> t);
+
+template<class T, class Compare>
+    pair<T, T>
+    minmax(initializer_list<T> t, Compare comp);
+
+template <class InputIterator1, class InputIterator2>
+    bool
+    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
+
+template <class InputIterator1, class InputIterator2, class Compare>
+    bool
+    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
+                            InputIterator2 first2, InputIterator2 last2, Compare comp);
+
+template <class BidirectionalIterator>
+    bool
+    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    bool
+    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
+
+template <class BidirectionalIterator>
+    bool
+    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    bool
+    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <initializer_list>
+#include <type_traits>
+#include <cstring>
+#include <utility>
+#include <memory>
+#include <iterator>
+#include <cstddef>
+
+#if defined(__IBMCPP__)
+#include "support/ibm/support.h"
+#endif
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+#include "support/win32/support.h"
+#endif
+
+#include <__undef_min_max>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _T1, class _T2 = _T1>
+struct __equal_to
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<_T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<const _T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<_T1, const _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1, class _T2 = _T1>
+struct __less
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<const _T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, const _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _Predicate>
+class __negate
+{
+private:
+    _Predicate __p_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __negate() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __negate(_Predicate __p) : __p_(__p) {}
+
+    template <class _T1>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x) {return !__p_(__x);}
+
+    template <class _T1, class _T2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x, const _T2& __y) {return !__p_(__x, __y);}
+};
+
+#ifdef _LIBCPP_DEBUG
+
+template <class _Compare>
+struct __debug_less
+{
+    _Compare __comp_;
+    __debug_less(_Compare& __c) : __comp_(__c) {}
+    template <class _Tp, class _Up>
+    bool operator()(const _Tp& __x, const _Up& __y)
+    {
+        bool __r = __comp_(__x, __y);
+        if (__r)
+            _LIBCPP_ASSERT(!__comp_(__y, __x), "Comparator does not induce a strict weak ordering");
+        return __r;
+    }
+};
+
+#endif  // _LIBCPP_DEBUG
+
+// Precondition:  __x != 0
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned
+__ctz(unsigned __x)
+{
+    return static_cast<unsigned>(__builtin_ctz(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned long
+__ctz(unsigned long __x)
+{
+    return static_cast<unsigned long>(__builtin_ctzl(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned long long
+__ctz(unsigned long long __x)
+{
+    return static_cast<unsigned long long>(__builtin_ctzll(__x));
+}
+
+// Precondition:  __x != 0
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned
+__clz(unsigned __x)
+{
+    return static_cast<unsigned>(__builtin_clz(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned long
+__clz(unsigned long __x)
+{
+    return static_cast<unsigned long>(__builtin_clzl (__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+unsigned long long
+__clz(unsigned long long __x)
+{
+    return static_cast<unsigned long long>(__builtin_clzll(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned           __x) {return __builtin_popcount  (__x);}
+inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned      long __x) {return __builtin_popcountl (__x);}
+inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {return __builtin_popcountll(__x);}
+
+// all_of
+
+template <class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (!__pred(*__first))
+            return false;
+    return true;
+}
+
+// any_of
+
+template <class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            return true;
+    return false;
+}
+
+// none_of
+
+template <class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            return false;
+    return true;
+}
+
+// for_each
+
+template <class _InputIterator, class _Function>
+inline _LIBCPP_INLINE_VISIBILITY
+_Function
+for_each(_InputIterator __first, _InputIterator __last, _Function __f)
+{
+    for (; __first != __last; ++__first)
+        __f(*__first);
+    return _VSTD::move(__f);  // explicitly moved for (emulated) C++03
+}
+
+// find
+
+template <class _InputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_InputIterator
+find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
+{
+    for (; __first != __last; ++__first)
+        if (*__first == __value_)
+            break;
+    return __first;
+}
+
+// find_if
+
+template <class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_InputIterator
+find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            break;
+    return __first;
+}
+
+// find_if_not
+
+template<class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_InputIterator
+find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (!__pred(*__first))
+            break;
+    return __first;
+}
+
+// find_end
+
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+_ForwardIterator1
+__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
+           forward_iterator_tag, forward_iterator_tag)
+{
+    // modeled after search algorithm
+    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
+    if (__first2 == __last2)
+        return __r;
+    while (true)
+    {
+        while (true)
+        {
+            if (__first1 == __last1)         // if source exhausted return last correct answer
+                return __r;                  //    (or __last1 if never found)
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        }
+        // *__first1 matches *__first2, now match elements after here
+        _ForwardIterator1 __m1 = __first1;
+        _ForwardIterator2 __m2 = __first2;
+        while (true)
+        {
+            if (++__m2 == __last2)
+            {                         // Pattern exhaused, record answer and search for another one
+                __r = __first1;
+                ++__first1;
+                break;
+            }
+            if (++__m1 == __last1)     // Source exhausted, return last answer
+                return __r;
+            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
+            {
+                ++__first1;
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
+_BidirectionalIterator1
+__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
+           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
+           bidirectional_iterator_tag, bidirectional_iterator_tag)
+{
+    // modeled after search algorithm (in reverse)
+    if (__first2 == __last2)
+        return __last1;  // Everything matches an empty sequence
+    _BidirectionalIterator1 __l1 = __last1;
+    _BidirectionalIterator2 __l2 = __last2;
+    --__l2;
+    while (true)
+    {
+        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
+        while (true)
+        {
+            if (__first1 == __l1)  // return __last1 if no element matches *__first2
+                return __last1;
+            if (__pred(*--__l1, *__l2))
+                break;
+        }
+        // *__l1 matches *__l2, now match elements before here
+        _BidirectionalIterator1 __m1 = __l1;
+        _BidirectionalIterator2 __m2 = __l2;
+        while (true)
+        {
+            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
+                return __m1;
+            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
+                return __last1;
+            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
+            {
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator1
+__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
+           random_access_iterator_tag, random_access_iterator_tag)
+{
+    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
+    if (__len2 == 0)
+        return __last1;
+    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
+    if (__len1 < __len2)
+        return __last1;
+    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
+    _RandomAccessIterator1 __l1 = __last1;
+    _RandomAccessIterator2 __l2 = __last2;
+    --__l2;
+    while (true)
+    {
+        while (true)
+        {
+            if (__s == __l1)
+                return __last1;
+            if (__pred(*--__l1, *__l2))
+                break;
+        }
+        _RandomAccessIterator1 __m1 = __l1;
+        _RandomAccessIterator2 __m2 = __l2;
+        while (true)
+        {
+            if (__m2 == __first2)
+                return __m1;
+                                 // no need to check range on __m1 because __s guarantees we have enough source
+            if (!__pred(*--__m1, *--__m2))
+            {
+                break;
+            }
+        }
+    }
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator1
+find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
+{
+    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
+                         (__first1, __last1, __first2, __last2, __pred,
+                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
+                          typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator1
+find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+// find_first_of
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
+{
+    for (; __first1 != __last1; ++__first1)
+        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+            if (__pred(*__first1, *__j))
+                return __first1;
+    return __last1;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator1
+find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+    return _VSTD::find_first_of(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+// adjacent_find
+
+template <class _ForwardIterator, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__pred(*__first, *__i))
+                return __first;
+            __first = __i;
+        }
+    }
+    return __last;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
+}
+
+// count
+
+template <class _InputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename iterator_traits<_InputIterator>::difference_type
+count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
+{
+    typename iterator_traits<_InputIterator>::difference_type __r(0);
+    for (; __first != __last; ++__first)
+        if (*__first == __value_)
+            ++__r;
+    return __r;
+}
+
+// count_if
+
+template <class _InputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+typename iterator_traits<_InputIterator>::difference_type
+count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    typename iterator_traits<_InputIterator>::difference_type __r(0);
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            ++__r;
+    return __r;
+}
+
+// mismatch
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_InputIterator1, _InputIterator2>
+mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+         _InputIterator2 __first2, _BinaryPredicate __pred)
+{
+    for (; __first1 != __last1; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            break;
+    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_InputIterator1, _InputIterator2>
+mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_InputIterator1, _InputIterator2>
+mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+         _InputIterator2 __first2, _InputIterator2 __last2,
+         _BinaryPredicate __pred)
+{
+    for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            break;
+    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_InputIterator1, _InputIterator2>
+mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
+         _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+#endif
+
+// equal
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
+{
+    for (; __first1 != __last1; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            return false;
+    return true;
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+__equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
+        input_iterator_tag, input_iterator_tag )
+{
+    for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            return false;
+    return __first1 == __last1 && __first2 == __last2;
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, 
+        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred, 
+      random_access_iterator_tag, random_access_iterator_tag )
+{
+    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+        return false;
+    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
+                        typename add_lvalue_reference<_BinaryPredicate>::type>
+                       (__first1, __last1, __first2, __pred );
+}
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
+{
+    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
+       (__first1, __last1, __first2, __last2, __pred, 
+        typename iterator_traits<_InputIterator1>::iterator_category(),
+        typename iterator_traits<_InputIterator2>::iterator_category());
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, 
+      _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
+        typename iterator_traits<_InputIterator1>::iterator_category(),
+        typename iterator_traits<_InputIterator2>::iterator_category());
+}
+#endif
+
+// is_permutation
+
+template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _BinaryPredicate __pred)
+{
+    // shorten sequences as much as possible by lopping of any equal parts
+    for (; __first1 != __last1; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            goto __not_done;
+    return true;
+__not_done:
+    // __first1 != __last1 && *__first1 != *__first2
+    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+    _D1 __l1 = _VSTD::distance(__first1, __last1);
+    if (__l1 == _D1(1))
+        return false;
+    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
+    // For each element in [f1, l1) see if there are the same number of
+    //    equal elements in [f2, l2)
+    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
+    {
+        // Have we already counted the number of *__i in [f1, l1)?
+        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
+            if (__pred(*__j, *__i))
+                goto __next_iter;
+        {
+            // Count number of *__i in [f2, l2)
+            _D1 __c2 = 0;
+            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+                if (__pred(*__i, *__j))
+                    ++__c2;
+            if (__c2 == 0)
+                return false;
+            // Count number of *__i in [__i, l1) (we can start with 1)
+            _D1 __c1 = 1;
+            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+                if (__pred(*__i, *__j))
+                    ++__c1;
+            if (__c1 != __c2)
+                return false;
+        }
+__next_iter:;
+    }
+    return true;
+}
+
+template<class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+bool
+__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, 
+                 _BinaryPredicate __pred,
+                 forward_iterator_tag, forward_iterator_tag )
+{
+    // shorten sequences as much as possible by lopping of any equal parts
+    for (; __first1 != __last1 && __first2 != __last2; ++__first1, ++__first2)
+        if (!__pred(*__first1, *__first2))
+            goto __not_done;
+    return __first1 == __last1 && __first2 == __last2;
+__not_done:
+    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
+    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+    _D1 __l1 = _VSTD::distance(__first1, __last1);
+
+    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
+    _D2 __l2 = _VSTD::distance(__first2, __last2);
+    if (__l1 != __l2)
+        return false;
+
+    // For each element in [f1, l1) see if there are the same number of
+    //    equal elements in [f2, l2)
+    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
+    {
+        // Have we already counted the number of *__i in [f1, l1)?
+        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
+            if (__pred(*__j, *__i))
+                goto __next_iter;
+        {
+            // Count number of *__i in [f2, l2)
+            _D1 __c2 = 0;
+            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+                if (__pred(*__i, *__j))
+                    ++__c2;
+            if (__c2 == 0)
+                return false;
+            // Count number of *__i in [__i, l1) (we can start with 1)
+            _D1 __c1 = 1;
+            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+                if (__pred(*__i, *__j))
+                    ++__c1;
+            if (__c1 != __c2)
+                return false;
+        }
+__next_iter:;
+    }
+    return true;
+}
+
+template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+bool
+__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
+               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2, 
+               _BinaryPredicate __pred,
+               random_access_iterator_tag, random_access_iterator_tag )
+{
+    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+        return false;
+    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
+                                 typename add_lvalue_reference<_BinaryPredicate>::type>
+                                (__first1, __last1, __first2, __pred );
+}
+
+template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+               _BinaryPredicate __pred )
+{
+    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
+       (__first1, __last1, __first2, __last2, __pred,
+        typename iterator_traits<_ForwardIterator1>::iterator_category(),
+        typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template<class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
+        __equal_to<__v1, __v2>(),
+        typename iterator_traits<_ForwardIterator1>::iterator_category(),
+        typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+#endif
+
+// search
+
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+_ForwardIterator1
+__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
+         forward_iterator_tag, forward_iterator_tag)
+{
+    if (__first2 == __last2)
+        return __first1;  // Everything matches an empty sequence
+    while (true)
+    {
+        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
+        while (true)
+        {
+            if (__first1 == __last1)  // return __last1 if no element matches *__first2
+                return __last1;
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        }
+        // *__first1 matches *__first2, now match elements after here
+        _ForwardIterator1 __m1 = __first1;
+        _ForwardIterator2 __m2 = __first2;
+        while (true)
+        {
+            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
+                return __first1;
+            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
+                return __last1;
+            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
+            {
+                ++__first1;
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator1
+__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
+           random_access_iterator_tag, random_access_iterator_tag)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _D1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _D2;
+    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+    _D2 __len2 = __last2 - __first2;
+    if (__len2 == 0)
+        return __first1;
+    _D1 __len1 = __last1 - __first1;
+    if (__len1 < __len2)
+        return __last1;
+    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
+    while (true)
+    {
+#if !_LIBCPP_UNROLL_LOOPS
+        while (true)
+        {
+            if (__first1 == __s)
+                return __last1;
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        }
+#else  // !_LIBCPP_UNROLL_LOOPS
+        for (_D1 __loop_unroll = (__s - __first1) / 4; __loop_unroll > 0; --__loop_unroll)
+        {
+            if (__pred(*__first1, *__first2))
+                goto __phase2;
+            if (__pred(*++__first1, *__first2))
+                goto __phase2;
+            if (__pred(*++__first1, *__first2))
+                goto __phase2;
+            if (__pred(*++__first1, *__first2))
+                goto __phase2;
+            ++__first1;
+        }
+        switch (__s - __first1)
+        {
+        case 3:
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        case 2:
+            if (__pred(*__first1, *__first2))
+                break;
+            ++__first1;
+        case 1:
+            if (__pred(*__first1, *__first2))
+                break;
+        case 0:
+            return __last1;
+        }
+    __phase2:
+#endif  // !_LIBCPP_UNROLL_LOOPS
+        _RandomAccessIterator1 __m1 = __first1;
+        _RandomAccessIterator2 __m2 = __first2;
+#if !_LIBCPP_UNROLL_LOOPS
+         while (true)
+         {
+             if (++__m2 == __last2)
+                 return __first1;
+             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
+             if (!__pred(*__m1, *__m2))
+             {
+                 ++__first1;
+                 break;
+             }
+         }
+#else  // !_LIBCPP_UNROLL_LOOPS
+        ++__m2;
+        ++__m1;
+        for (_D2 __loop_unroll = (__last2 - __m2) / 4; __loop_unroll > 0; --__loop_unroll)
+        {
+            if (!__pred(*__m1, *__m2))
+                goto __continue;
+            if (!__pred(*++__m1, *++__m2))
+                goto __continue;
+            if (!__pred(*++__m1, *++__m2))
+                goto __continue;
+            if (!__pred(*++__m1, *++__m2))
+                goto __continue;
+            ++__m1;
+            ++__m2;
+        }
+        switch (__last2 - __m2)
+        {
+        case 3:
+            if (!__pred(*__m1, *__m2))
+                break;
+            ++__m1;
+            ++__m2;
+        case 2:
+            if (!__pred(*__m1, *__m2))
+                break;
+            ++__m1;
+            ++__m2;
+        case 1:
+            if (!__pred(*__m1, *__m2))
+                break;
+        case 0:
+            return __first1;
+        }
+    __continue:
+        ++__first1;
+#endif  // !_LIBCPP_UNROLL_LOOPS
+    }
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator1
+search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
+{
+    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
+                         (__first1, __last1, __first2, __last2, __pred,
+                          typename std::iterator_traits<_ForwardIterator1>::iterator_category(),
+                          typename std::iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator1
+search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+{
+    typedef typename std::iterator_traits<_ForwardIterator1>::value_type __v1;
+    typedef typename std::iterator_traits<_ForwardIterator2>::value_type __v2;
+    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+// search_n
+
+template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
+_ForwardIterator
+__search_n(_ForwardIterator __first, _ForwardIterator __last,
+           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
+{
+    if (__count <= 0)
+        return __first;
+    while (true)
+    {
+        // Find first element in sequence that matchs __value_, with a mininum of loop checks
+        while (true)
+        {
+            if (__first == __last)  // return __last if no element matches __value_
+                return __last;
+            if (__pred(*__first, __value_))
+                break;
+            ++__first;
+        }
+        // *__first matches __value_, now match elements after here
+        _ForwardIterator __m = __first;
+        _Size __c(0);
+        while (true)
+        {
+            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
+                return __first;
+            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
+                return __last;
+            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
+            {
+                __first = __m;
+                ++__first;
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
+_RandomAccessIterator
+__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
+           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
+{
+    if (__count <= 0)
+        return __first;
+    _Size __len = static_cast<_Size>(__last - __first);
+    if (__len < __count)
+        return __last;
+    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
+    while (true)
+    {
+        // Find first element in sequence that matchs __value_, with a mininum of loop checks
+        while (true)
+        {
+            if (__first >= __s)  // return __last if no element matches __value_
+                return __last;
+            if (__pred(*__first, __value_))
+                break;
+            ++__first;
+        }
+        // *__first matches __value_, now match elements after here
+        _RandomAccessIterator __m = __first;
+        _Size __c(0);
+        while (true)
+        {
+            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
+                return __first;
+             ++__m;          // no need to check range on __m because __s guarantees we have enough source
+            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
+            {
+                __first = __m;
+                ++__first;
+                break;
+            }  // else there is a match, check next elements
+        }
+    }
+}
+
+template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+search_n(_ForwardIterator __first, _ForwardIterator __last,
+         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
+{
+    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
+           (__first, __last, __count, __value_, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+template <class _ForwardIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+    return _VSTD::search_n(__first, __last, __count, __value_, __equal_to<__v, _Tp>());
+}
+
+// copy
+
+template <class _Iter>
+struct __libcpp_is_trivial_iterator
+{
+    static const bool value = is_pointer<_Iter>::value;
+};
+
+template <class _Iter>
+struct __libcpp_is_trivial_iterator<move_iterator<_Iter> >
+{
+    static const bool value = is_pointer<_Iter>::value;
+};
+
+template <class _Iter>
+struct __libcpp_is_trivial_iterator<__wrap_iter<_Iter> >
+{
+    static const bool value = is_pointer<_Iter>::value;
+};
+
+template <class _Iter>
+inline _LIBCPP_INLINE_VISIBILITY
+_Iter
+__unwrap_iter(_Iter __i)
+{
+    return __i;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_trivially_copy_assignable<_Tp>::value,
+    _Tp*
+>::type
+__unwrap_iter(move_iterator<_Tp*> __i)
+{
+    return __i.base();
+}
+
+#if _LIBCPP_DEBUG_LEVEL < 2
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_trivially_copy_assignable<_Tp>::value,
+    _Tp*
+>::type
+__unwrap_iter(__wrap_iter<_Tp*> __i)
+{
+    return __i.base();
+}
+
+#endif  // _LIBCPP_DEBUG_LEVEL < 2
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__first, ++__result)
+        *__result = *__first;
+    return __result;
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__copy(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result + __n;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
+}
+
+// copy_backward
+
+template <class _BidirectionalIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
+{
+    while (__first != __last)
+        *--__result = *--__last;
+    return __result;
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    __result -= __n;
+    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result;
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+_BidirectionalIterator2
+copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+    return _VSTD::__copy_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
+}
+
+// copy_if
+
+template<class _InputIterator, class _OutputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+copy_if(_InputIterator __first, _InputIterator __last,
+        _OutputIterator __result, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+// copy_n
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_input_iterator<_InputIterator>::value &&
+   !__is_random_access_iterator<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+{
+    if (__n > 0)
+    {
+        *__result = *__first;
+        ++__result;
+        for (--__n; __n > 0; --__n)
+        {
+            ++__first;
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_random_access_iterator<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
+{
+    return _VSTD::copy(__first, __first + __n, __result);
+}
+
+// move
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__first, ++__result)
+        *__result = _VSTD::move(*__first);
+    return __result;
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__move(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result + __n;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
+}
+
+// move_backward
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    while (__first != __last)
+        *--__result = _VSTD::move(*--__last);
+    return __result;
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    __result -= __n;
+    _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result;
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+_BidirectionalIterator2
+move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
+}
+
+// iter_swap
+
+// moved to <type_traits> for better swap / noexcept support
+
+// transform
+
+template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
+{
+    for (; __first != __last; ++__first, ++__result)
+        *__result = __op(*__first);
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
+          _OutputIterator __result, _BinaryOperation __binary_op)
+{
+    for (; __first1 != __last1; ++__first1, ++__first2, ++__result)
+        *__result = __binary_op(*__first1, *__first2);
+    return __result;
+}
+
+// replace
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first)
+        if (*__first == __old_value)
+            *__first = __new_value;
+}
+
+// replace_if
+
+template <class _ForwardIterator, class _Predicate, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            *__first = __new_value;
+}
+
+// replace_copy
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+             const _Tp& __old_value, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first, ++__result)
+        if (*__first == __old_value)
+            *__result = __new_value;
+        else
+            *__result = *__first;
+    return __result;
+}
+
+// replace_copy_if
+
+template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+                _Predicate __pred, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first, ++__result)
+        if (__pred(*__first))
+            *__result = __new_value;
+        else
+            *__result = *__first;
+    return __result;
+}
+
+// fill_n
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
+{
+    for (; __n > 0; ++__first, --__n)
+        *__first = __value_;
+    return __first;
+}
+
+template <class _Tp, class _Size, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
+    !is_same<_Tp, bool>::value &&
+    is_integral<_Up>::value && sizeof(_Up) == 1,
+    _Tp*
+>::type
+__fill_n(_Tp* __first, _Size __n,_Up __value_)
+{
+    if (__n > 0)
+        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
+    return __first + __n;
+}
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
+{
+   return _VSTD::__fill_n(__first, __n, __value_);
+}
+
+// fill
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
+{
+    for (; __first != __last; ++__first)
+        *__first = __value_;
+}
+
+template <class _RandomAccessIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
+{
+    _VSTD::fill_n(__first, __last - __first, __value_);
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+// generate
+
+template <class _ForwardIterator, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
+{
+    for (; __first != __last; ++__first)
+        *__first = __gen();
+}
+
+// generate_n
+
+template <class _OutputIterator, class _Size, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
+{
+    for (; __n > 0; ++__first, --__n)
+        *__first = __gen();
+    return __first;
+}
+
+// remove
+
+template <class _ForwardIterator, class _Tp>
+_ForwardIterator
+remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    __first = _VSTD::find(__first, __last, __value_);
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (!(*__i == __value_))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+        }
+    }
+    return __first;
+}
+
+// remove_if
+
+template <class _ForwardIterator, class _Predicate>
+_ForwardIterator
+remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
+                           (__first, __last, __pred);
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (!__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+        }
+    }
+    return __first;
+}
+
+// remove_copy
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (!(*__first == __value_))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+// remove_copy_if
+
+template <class _InputIterator, class _OutputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (!__pred(*__first))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+// unique
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
+{
+    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
+                                 (__first, __last, __pred);
+    if (__first != __last)
+    {
+        // ...  a  a  ?  ...
+        //      f     i
+        _ForwardIterator __i = __first;
+        for (++__i; ++__i != __last;)
+            if (!__pred(*__first, *__i))
+                *++__first = _VSTD::move(*__i);
+        ++__first;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+unique(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+    return _VSTD::unique(__first, __last, __equal_to<__v>());
+}
+
+// unique_copy
+
+template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
+_OutputIterator
+__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
+              input_iterator_tag, output_iterator_tag)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __t(*__first);
+        *__result = __t;
+        ++__result;
+        while (++__first != __last)
+        {
+            if (!__pred(__t, *__first))
+            {
+                __t = *__first;
+                *__result = __t;
+                ++__result;
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
+              forward_iterator_tag, output_iterator_tag)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        *__result = *__i;
+        ++__result;
+        while (++__first != __last)
+        {
+            if (!__pred(*__i, *__first))
+            {
+                *__result = *__first;
+                ++__result;
+                __i = __first;
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
+_ForwardIterator
+__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
+              input_iterator_tag, forward_iterator_tag)
+{
+    if (__first != __last)
+    {
+        *__result = *__first;
+        while (++__first != __last)
+            if (!__pred(*__result, *__first))
+                *++__result = *__first;
+        ++__result;
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
+{
+    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
+                              (__first, __last, __result, __pred,
+                               typename iterator_traits<_InputIterator>::iterator_category(),
+                               typename iterator_traits<_OutputIterator>::iterator_category());
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type __v;
+    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
+}
+
+// reverse
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
+{
+    while (__first != __last)
+    {
+        if (__first == --__last)
+            break;
+        swap(*__first, *__last);
+        ++__first;
+    }
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
+{
+    if (__first != __last)
+        for (; __first < --__last; ++__first)
+            swap(*__first, *__last);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
+}
+
+// reverse_copy
+
+template <class _BidirectionalIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__result)
+        *__result = *--__last;
+    return __result;
+}
+
+// rotate
+
+template <class _ForwardIterator>
+_ForwardIterator
+__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+    value_type __tmp = _VSTD::move(*__first);
+    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
+    *__lm1 = _VSTD::move(__tmp);
+    return __lm1;
+}
+
+template <class _BidirectionalIterator>
+_BidirectionalIterator
+__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
+    value_type __tmp = _VSTD::move(*__lm1);
+    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
+    *__first = _VSTD::move(__tmp);
+    return __fp1;
+}
+
+template <class _ForwardIterator>
+_ForwardIterator
+__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
+{
+    _ForwardIterator __i = __middle;
+    while (true)
+    {
+        swap(*__first, *__i);
+        ++__first;
+        if (++__i == __last)
+            break;
+        if (__first == __middle)
+            __middle = __i;
+    }
+    _ForwardIterator __r = __first;
+    if (__first != __middle)
+    {
+        __i = __middle;
+        while (true)
+        {
+            swap(*__first, *__i);
+            ++__first;
+            if (++__i == __last)
+            {
+                if (__first == __middle)
+                    break;
+                __i = __middle;
+            }
+            else if (__first == __middle)
+                __middle = __i;
+        }
+    }
+    return __r;
+}
+
+template<typename _Integral>
+inline _LIBCPP_INLINE_VISIBILITY
+_Integral
+__gcd(_Integral __x, _Integral __y)
+{
+    do
+    {
+        _Integral __t = __x % __y;
+        __x = __y;
+        __y = __t;
+    } while (__y);
+    return __x;
+}
+
+template<typename _RandomAccessIterator>
+_RandomAccessIterator
+__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+
+    const difference_type __m1 = __middle - __first;
+    const difference_type __m2 = __last - __middle;
+    if (__m1 == __m2)
+    {
+        _VSTD::swap_ranges(__first, __middle, __middle);
+        return __middle;
+    }
+    const difference_type __g = _VSTD::__gcd(__m1, __m2);
+    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
+    {
+        value_type __t(_VSTD::move(*--__p));
+        _RandomAccessIterator __p1 = __p;
+        _RandomAccessIterator __p2 = __p1 + __m1;
+        do
+        {
+            *__p1 = _VSTD::move(*__p2);
+            __p1 = __p2;
+            const difference_type __d = __last - __p2;
+            if (__m1 < __d)
+                __p2 += __m1;
+            else
+                __p2 = __first + (__m1 - __d);
+        } while (__p2 != __p);
+        *__p1 = _VSTD::move(__t);
+    }
+    return __first + __m2;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
+         _VSTD::forward_iterator_tag)
+{
+    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
+    if (_VSTD::is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_BidirectionalIterator
+__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+         _VSTD::bidirectional_iterator_tag)
+{
+    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
+    if (_VSTD::is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+        if (_VSTD::next(__middle) == __last)
+            return _VSTD::__rotate_right(__first, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_RandomAccessIterator
+__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+         _VSTD::random_access_iterator_tag)
+{
+    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
+    if (_VSTD::is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+        if (_VSTD::next(__middle) == __last)
+            return _VSTD::__rotate_right(__first, __last);
+        return _VSTD::__rotate_gcd(__first, __middle, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
+{
+    if (__first == __middle)
+        return __last;
+    if (__middle == __last)
+        return __first;
+    return _VSTD::__rotate(__first, __middle, __last,
+                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+// rotate_copy
+
+template <class _ForwardIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
+{
+    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
+}
+
+// min_element
+
+template <class _ForwardIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+            if (__comp(*__i, *__first))
+                __first = __i;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::min_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// min
+
+template <class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp&
+min(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? __b : __a;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp&
+min(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::min(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template<class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+min(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+min(initializer_list<_Tp> __t)
+{
+    return *_VSTD::min_element(__t.begin(), __t.end());
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+// max_element
+
+template <class _ForwardIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+            if (__comp(*__first, *__i))
+                __first = __i;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::max_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// max
+
+template <class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp&
+max(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__a, __b) ? __b : __a;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp&
+max(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::max(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template<class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+max(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+max(initializer_list<_Tp> __t)
+{
+    return *_VSTD::max_element(__t.begin(), __t.end());
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+// minmax_element
+
+template <class _ForwardIterator, class _Compare>
+std::pair<_ForwardIterator, _ForwardIterator>
+minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
+  if (__first != __last)
+  {
+      if (++__first != __last)
+      {
+          if (__comp(*__first, *__result.first))
+              __result.first = __first;
+          else
+              __result.second = __first;
+          while (++__first != __last)
+          {
+              _ForwardIterator __i = __first;
+              if (++__first == __last)
+              {
+                  if (__comp(*__i, *__result.first))
+                      __result.first = __i;
+                  else if (!__comp(*__i, *__result.second))
+                      __result.second = __i;
+                  break;
+              }
+              else
+              {
+                  if (__comp(*__first, *__i))
+                  {
+                      if (__comp(*__first, *__result.first))
+                          __result.first = __first;
+                      if (!__comp(*__i, *__result.second))
+                          __result.second = __i;
+                  }
+                  else
+                  {
+                      if (__comp(*__i, *__result.first))
+                          __result.first = __i;
+                      if (!__comp(*__first, *__result.second))
+                          __result.second = __first;
+                  }
+              }
+          }
+      }
+  }
+  return __result;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+std::pair<_ForwardIterator, _ForwardIterator>
+minmax_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::minmax_element(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// minmax
+
+template<class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<const _Tp&, const _Tp&>
+minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
+                              pair<const _Tp&, const _Tp&>(__a, __b);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<const _Tp&, const _Tp&>
+minmax(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::minmax(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_Tp, _Tp>
+minmax(initializer_list<_Tp> __t)
+{
+    pair<const _Tp*, const _Tp*> __p =
+                                   _VSTD::minmax_element(__t.begin(), __t.end());
+    return pair<_Tp, _Tp>(*__p.first, *__p.second);
+}
+
+template<class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_Tp, _Tp>
+minmax(initializer_list<_Tp> __t, _Compare __comp)
+{
+    pair<const _Tp*, const _Tp*> __p =
+                           _VSTD::minmax_element(__t.begin(), __t.end(), __comp);
+    return pair<_Tp, _Tp>(*__p.first, *__p.second);
+}
+
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+
+// random_shuffle
+
+// __independent_bits_engine
+
+template <unsigned long long _Xp, size_t _Rp>
+struct __log2_imp
+{
+    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
+                                           : __log2_imp<_Xp, _Rp - 1>::value;
+};
+
+template <unsigned long long _Xp>
+struct __log2_imp<_Xp, 0>
+{
+    static const size_t value = 0;
+};
+
+template <size_t _Rp>
+struct __log2_imp<0, _Rp>
+{
+    static const size_t value = _Rp + 1;
+};
+
+template <class _UI, _UI _Xp>
+struct __log2
+{
+    static const size_t value = __log2_imp<_Xp,
+                                         sizeof(_UI) * __CHAR_BIT__ - 1>::value;
+};
+
+template<class _Engine, class _UIntType>
+class __independent_bits_engine
+{
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    typedef typename _Engine::result_type _Engine_result_type;
+    typedef typename conditional
+        <
+            sizeof(_Engine_result_type) <= sizeof(result_type),
+                result_type,
+                _Engine_result_type
+        >::type _Working_result_type;
+
+    _Engine& __e_;
+    size_t __w_;
+    size_t __w0_;
+    size_t __n_;
+    size_t __n0_;
+    _Working_result_type __y0_;
+    _Working_result_type __y1_;
+    _Engine_result_type __mask0_;
+    _Engine_result_type __mask1_;
+
+#ifdef _LIBCPP_HAS_NO_CONSTEXPR
+    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
+                                          + _Working_result_type(1);
+#else
+    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
+                                                      + _Working_result_type(1);
+#endif
+    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
+    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
+    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
+
+public:
+    // constructors and seeding functions
+    __independent_bits_engine(_Engine& __e, size_t __w);
+
+    // generating functions
+    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
+
+private:
+    result_type __eval(false_type);
+    result_type __eval(true_type);
+};
+
+template<class _Engine, class _UIntType>
+__independent_bits_engine<_Engine, _UIntType>
+    ::__independent_bits_engine(_Engine& __e, size_t __w)
+        : __e_(__e),
+          __w_(__w)
+{
+    __n_ = __w_ / __m + (__w_ % __m != 0);
+    __w0_ = __w_ / __n_;
+    if (_Rp == 0)
+        __y0_ = _Rp;
+    else if (__w0_ < _WDt)
+        __y0_ = (_Rp >> __w0_) << __w0_;
+    else
+        __y0_ = 0;
+    if (_Rp - __y0_ > __y0_ / __n_)
+    {
+        ++__n_;
+        __w0_ = __w_ / __n_;
+        if (__w0_ < _WDt)
+            __y0_ = (_Rp >> __w0_) << __w0_;
+        else
+            __y0_ = 0;
+    }
+    __n0_ = __n_ - __w_ % __n_;
+    if (__w0_ < _WDt - 1)
+        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
+    else
+        __y1_ = 0;
+    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
+                          _Engine_result_type(0);
+    __mask1_ = __w0_ < _EDt - 1 ?
+                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
+                               _Engine_result_type(~0);
+}
+
+template<class _Engine, class _UIntType>
+inline
+_UIntType
+__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
+{
+    return static_cast<result_type>(__e_() & __mask0_);
+}
+
+template<class _Engine, class _UIntType>
+_UIntType
+__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
+{
+    result_type _Sp = 0;
+    for (size_t __k = 0; __k < __n0_; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y0_);
+        if (__w0_ < _WDt)
+            _Sp <<= __w0_;
+        else
+            _Sp = 0;
+        _Sp += __u & __mask0_;
+    }
+    for (size_t __k = __n0_; __k < __n_; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y1_);
+        if (__w0_ < _WDt - 1)
+            _Sp <<= __w0_ + 1;
+        else
+            _Sp = 0;
+        _Sp += __u & __mask1_;
+    }
+    return _Sp;
+}
+
+// uniform_int_distribution
+
+template<class _IntType = int>
+class uniform_int_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef uniform_int_distribution distribution_type;
+
+        explicit param_type(result_type __a = 0,
+                            result_type __b = numeric_limits<result_type>::max())
+            : __a_(__a), __b_(__b) {}
+
+        result_type a() const {return __a_;}
+        result_type b() const {return __b_;}
+
+        friend bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+    explicit uniform_int_distribution(result_type __a = 0,
+                                      result_type __b = numeric_limits<result_type>::max())
+        : __p_(param_type(__a, __b)) {}
+    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
+    void reset() {}
+
+    // generating functions
+    template<class _URNG> result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    result_type a() const {return __p_.a();}
+    result_type b() const {return __p_.b();}
+
+    param_type param() const {return __p_;}
+    void param(const param_type& __p) {__p_ = __p;}
+
+    result_type min() const {return a();}
+    result_type max() const {return b();}
+
+    friend bool operator==(const uniform_int_distribution& __x,
+                           const uniform_int_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend bool operator!=(const uniform_int_distribution& __x,
+                           const uniform_int_distribution& __y)
+            {return !(__x == __y);}
+};
+
+template<class _IntType>
+template<class _URNG>
+typename uniform_int_distribution<_IntType>::result_type
+uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
+{
+    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
+                                            uint32_t, uint64_t>::type _UIntType;
+    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
+    if (_Rp == 1)
+        return __p.a();
+    const size_t _Dt = numeric_limits<_UIntType>::digits;
+    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
+    if (_Rp == 0)
+        return static_cast<result_type>(_Eng(__g, _Dt)());
+    size_t __w = _Dt - __clz(_Rp) - 1;
+    if ((_Rp & (_UIntType(~0) >> (_Dt - __w))) != 0)
+        ++__w;
+    _Eng __e(__g, __w);
+    _UIntType __u;
+    do
+    {
+        __u = __e();
+    } while (__u >= _Rp);
+    return static_cast<result_type>(__u + __p.a());
+}
+
+class _LIBCPP_TYPE_VIS __rs_default;
+
+_LIBCPP_FUNC_VIS __rs_default __rs_get();
+
+class _LIBCPP_TYPE_VIS __rs_default
+{
+    static unsigned __c_;
+
+    __rs_default();
+public:
+    typedef uint_fast32_t result_type;
+
+    static const result_type _Min = 0;
+    static const result_type _Max = 0xFFFFFFFF;
+
+    __rs_default(const __rs_default&);
+    ~__rs_default();
+
+    result_type operator()();
+
+    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
+    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
+
+    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
+};
+
+_LIBCPP_FUNC_VIS __rs_default __rs_get();
+
+template <class _RandomAccessIterator>
+void
+random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef uniform_int_distribution<ptrdiff_t> _Dp;
+    typedef typename _Dp::param_type _Pp;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        _Dp __uid;
+        __rs_default __g = __rs_get();
+        for (--__last, --__d; __first < __last; ++__first, --__d)
+        {
+            difference_type __i = __uid(__g, _Pp(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _RandomNumberGenerator>
+void
+random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+               _RandomNumberGenerator&& __rand)
+#else
+               _RandomNumberGenerator& __rand)
+#endif
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        for (--__last; __first < __last; ++__first, --__d)
+        {
+            difference_type __i = __rand(__d);
+            swap(*__first, *(__first + __i));
+        }
+    }
+}
+
+template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
+    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
+                 _UniformRandomNumberGenerator&& __g)
+#else
+                 _UniformRandomNumberGenerator& __g)
+#endif
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef uniform_int_distribution<ptrdiff_t> _Dp;
+    typedef typename _Dp::param_type _Pp;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        _Dp __uid;
+        for (--__last, --__d; __first < __last; ++__first, --__d)
+        {
+            difference_type __i = __uid(__g, _Pp(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
+    }
+}
+
+template <class _InputIterator, class _Predicate>
+bool
+is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (!__pred(*__first))
+            break;
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            return false;
+    return true;
+}
+
+// partition
+
+template <class _Predicate, class _ForwardIterator>
+_ForwardIterator
+__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
+{
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    for (_ForwardIterator __p = __first; ++__p != __last;)
+    {
+        if (__pred(*__p))
+        {
+            swap(*__first, *__p);
+            ++__first;
+        }
+    }
+    return __first;
+}
+
+template <class _Predicate, class _BidirectionalIterator>
+_BidirectionalIterator
+__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+            bidirectional_iterator_tag)
+{
+    while (true)
+    {
+        while (true)
+        {
+            if (__first == __last)
+                return __first;
+            if (!__pred(*__first))
+                break;
+            ++__first;
+        }
+        do
+        {
+            if (__first == --__last)
+                return __first;
+        } while (!__pred(*__last));
+        swap(*__first, *__last);
+        ++__first;
+    }
+}
+
+template <class _ForwardIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
+                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+// partition_copy
+
+template <class _InputIterator, class _OutputIterator1,
+          class _OutputIterator2, class _Predicate>
+pair<_OutputIterator1, _OutputIterator2>
+partition_copy(_InputIterator __first, _InputIterator __last,
+               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
+               _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__out_true = *__first;
+            ++__out_true;
+        }
+        else
+        {
+            *__out_false = *__first;
+            ++__out_false;
+        }
+    }
+    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
+}
+
+// partition_point
+
+template<class _ForwardIterator, class _Predicate>
+_ForwardIterator
+partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = __len / 2;
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__pred(*__m))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else
+            __len = __l2;
+    }
+    return __first;
+}
+
+// stable_partition
+
+template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
+_ForwardIterator
+__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
+{
+    // *__first is known to be false
+    // __len >= 1
+    if (__len == 1)
+        return __first;
+    if (__len == 2)
+    {
+        _ForwardIterator __m = __first;
+        if (__pred(*++__m))
+        {
+            swap(*__first, *__m);
+            return __m;
+        }
+        return __first;
+    }
+    if (__len <= __p.second)
+    {   // The buffer is big enough to use
+        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
+        // Move the falses into the temporary buffer, and the trues to the front of the line
+        // Update __first to always point to the end of the trues
+        value_type* __t = __p.first;
+        ::new(__t) value_type(_VSTD::move(*__first));
+        __d.__incr((value_type*)0);
+        ++__t;
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+            else
+            {
+                ::new(__t) value_type(_VSTD::move(*__i));
+                __d.__incr((value_type*)0);
+                ++__t;
+            }
+        }
+        // All trues now at start of range, all falses in buffer
+        // Move falses back into range, but don't mess up __first which points to first false
+        __i = __first;
+        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
+            *__i = _VSTD::move(*__t2);
+        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
+        return __first;
+    }
+    // Else not enough buffer, do in place
+    // __len >= 3
+    _ForwardIterator __m = __first;
+    _Distance __len2 = __len / 2;  // __len2 >= 2
+    _VSTD::advance(__m, __len2);
+    // recurse on [__first, __m), *__first know to be false
+    // F?????????????????
+    // f       m         l
+    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
+    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
+    // TTTFFFFF??????????
+    // f  ff   m         l
+    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
+    _ForwardIterator __m1 = __m;
+    _ForwardIterator __second_false = __last;
+    _Distance __len_half = __len - __len2;
+    while (__pred(*__m1))
+    {
+        if (++__m1 == __last)
+            goto __second_half_done;
+        --__len_half;
+    }
+    // TTTFFFFFTTTF??????
+    // f  ff   m  m1     l
+    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
+__second_half_done:
+    // TTTFFFFFTTTTTFFFFF
+    // f  ff   m    sf   l
+    return _VSTD::rotate(__first_false, __m, __second_false);
+    // TTTTTTTTFFFFFFFFFF
+    //         |
+}
+
+struct __return_temporary_buffer
+{
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
+};
+
+template <class _Predicate, class _ForwardIterator>
+_ForwardIterator
+__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+                   forward_iterator_tag)
+{
+    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
+    // Either prove all true and return __first or point to first false
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    // We now have a reduced range [__first, __last)
+    // *__first is known to be false
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    pair<value_type*, ptrdiff_t> __p(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len >= __alloc_limit)
+    {
+        __p = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__p.first);
+    }
+    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
+                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
+}
+
+template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
+_BidirectionalIterator
+__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
+{
+    // *__first is known to be false
+    // *__last is known to be true
+    // __len >= 2
+    if (__len == 2)
+    {
+        swap(*__first, *__last);
+        return __last;
+    }
+    if (__len == 3)
+    {
+        _BidirectionalIterator __m = __first;
+        if (__pred(*++__m))
+        {
+            swap(*__first, *__m);
+            swap(*__m, *__last);
+            return __last;
+        }
+        swap(*__m, *__last);
+        swap(*__first, *__m);
+        return __m;
+    }
+    if (__len <= __p.second)
+    {   // The buffer is big enough to use
+        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
+        // Move the falses into the temporary buffer, and the trues to the front of the line
+        // Update __first to always point to the end of the trues
+        value_type* __t = __p.first;
+        ::new(__t) value_type(_VSTD::move(*__first));
+        __d.__incr((value_type*)0);
+        ++__t;
+        _BidirectionalIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+            else
+            {
+                ::new(__t) value_type(_VSTD::move(*__i));
+                __d.__incr((value_type*)0);
+                ++__t;
+            }
+        }
+        // move *__last, known to be true
+        *__first = _VSTD::move(*__i);
+        __i = ++__first;
+        // All trues now at start of range, all falses in buffer
+        // Move falses back into range, but don't mess up __first which points to first false
+        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
+            *__i = _VSTD::move(*__t2);
+        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
+        return __first;
+    }
+    // Else not enough buffer, do in place
+    // __len >= 4
+    _BidirectionalIterator __m = __first;
+    _Distance __len2 = __len / 2;  // __len2 >= 2
+    _VSTD::advance(__m, __len2);
+    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
+    // F????????????????T
+    // f       m        l
+    _BidirectionalIterator __m1 = __m;
+    _BidirectionalIterator __first_false = __first;
+    _Distance __len_half = __len2;
+    while (!__pred(*--__m1))
+    {
+        if (__m1 == __first)
+            goto __first_half_done;
+        --__len_half;
+    }
+    // F???TFFF?????????T
+    // f   m1  m        l
+    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
+    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
+__first_half_done:
+    // TTTFFFFF?????????T
+    // f  ff   m        l
+    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
+    __m1 = __m;
+    _BidirectionalIterator __second_false = __last;
+    ++__second_false;
+    __len_half = __len - __len2;
+    while (__pred(*__m1))
+    {
+        if (++__m1 == __last)
+            goto __second_half_done;
+        --__len_half;
+    }
+    // TTTFFFFFTTTF?????T
+    // f  ff   m  m1    l
+    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
+__second_half_done:
+    // TTTFFFFFTTTTTFFFFF
+    // f  ff   m    sf  l
+    return _VSTD::rotate(__first_false, __m, __second_false);
+    // TTTTTTTTFFFFFFFFFF
+    //         |
+}
+
+template <class _Predicate, class _BidirectionalIterator>
+_BidirectionalIterator
+__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+                   bidirectional_iterator_tag)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
+    // Either prove all true and return __first or point to first false
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    // __first points to first false, everything prior to __first is already set.
+    // Either prove [__first, __last) is all false and return __first, or point __last to last true
+    do
+    {
+        if (__first == --__last)
+            return __first;
+    } while (!__pred(*__last));
+    // We now have a reduced range [__first, __last]
+    // *__first is known to be false
+    // *__last is known to be true
+    // __len >= 2
+    difference_type __len = _VSTD::distance(__first, __last) + 1;
+    pair<value_type*, ptrdiff_t> __p(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len >= __alloc_limit)
+    {
+        __p = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__p.first);
+    }
+    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
+                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
+}
+
+template <class _ForwardIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
+                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+// is_sorted_until
+
+template <class _ForwardIterator, class _Compare>
+_ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__comp(*__i, *__first))
+                return __i;
+            __first = __i;
+        }
+    }
+    return __last;
+}
+
+template<class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// is_sorted
+
+template <class _ForwardIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
+}
+
+template<class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// sort
+
+// stable, 2-3 compares, 0-2 swaps
+
+template <class _Compare, class _ForwardIterator>
+unsigned
+__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
+{
+    unsigned __r = 0;
+    if (!__c(*__y, *__x))          // if x <= y
+    {
+        if (!__c(*__z, *__y))      // if y <= z
+            return __r;            // x <= y && y <= z
+                                   // x <= y && y > z
+        swap(*__y, *__z);          // x <= z && y < z
+        __r = 1;
+        if (__c(*__y, *__x))       // if x > y
+        {
+            swap(*__x, *__y);      // x < y && y <= z
+            __r = 2;
+        }
+        return __r;                // x <= y && y < z
+    }
+    if (__c(*__z, *__y))           // x > y, if y > z
+    {
+        swap(*__x, *__z);          // x < y && y < z
+        __r = 1;
+        return __r;
+    }
+    swap(*__x, *__y);              // x > y && y <= z
+    __r = 1;                       // x < y && x <= z
+    if (__c(*__z, *__y))           // if y > z
+    {
+        swap(*__y, *__z);          // x <= y && y < z
+        __r = 2;
+    }
+    return __r;
+}                                  // x <= y && y <= z
+
+// stable, 3-6 compares, 0-5 swaps
+
+template <class _Compare, class _ForwardIterator>
+unsigned
+__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
+            _ForwardIterator __x4, _Compare __c)
+{
+    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
+    if (__c(*__x4, *__x3))
+    {
+        swap(*__x3, *__x4);
+        ++__r;
+        if (__c(*__x3, *__x2))
+        {
+            swap(*__x2, *__x3);
+            ++__r;
+            if (__c(*__x2, *__x1))
+            {
+                swap(*__x1, *__x2);
+                ++__r;
+            }
+        }
+    }
+    return __r;
+}
+
+// stable, 4-10 compares, 0-9 swaps
+
+template <class _Compare, class _ForwardIterator>
+unsigned
+__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
+            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
+{
+    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
+    if (__c(*__x5, *__x4))
+    {
+        swap(*__x4, *__x5);
+        ++__r;
+        if (__c(*__x4, *__x3))
+        {
+            swap(*__x3, *__x4);
+            ++__r;
+            if (__c(*__x3, *__x2))
+            {
+                swap(*__x2, *__x3);
+                ++__r;
+                if (__c(*__x2, *__x1))
+                {
+                    swap(*__x1, *__x2);
+                    ++__r;
+                }
+            }
+        }
+    }
+    return __r;
+}
+
+// Assumes size > 0
+template <class _Compare, class _BirdirectionalIterator>
+void
+__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
+{
+    _BirdirectionalIterator __lm1 = __last;
+    for (--__lm1; __first != __lm1; ++__first)
+    {
+        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
+                                                        typename add_lvalue_reference<_Compare>::type>
+                                                       (__first, __last, __comp);
+        if (__i != __first)
+            swap(*__first, *__i);
+    }
+}
+
+template <class _Compare, class _BirdirectionalIterator>
+void
+__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
+    if (__first != __last)
+    {
+        _BirdirectionalIterator __i = __first;
+        for (++__i; __i != __last; ++__i)
+        {
+            _BirdirectionalIterator __j = __i;
+            value_type __t(_VSTD::move(*__j));
+            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
+                *__j = _VSTD::move(*__k);
+            *__j = _VSTD::move(__t);
+        }
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    _RandomAccessIterator __j = __first+2;
+    __sort3<_Compare>(__first, __first+1, __j, __comp);
+    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__j))
+        {
+            value_type __t(_VSTD::move(*__i));
+            _RandomAccessIterator __k = __j;
+            __j = __i;
+            do
+            {
+                *__j = _VSTD::move(*__k);
+                __j = __k;
+            } while (__j != __first && __comp(__t, *--__k));
+            *__j = _VSTD::move(__t);
+        }
+        __j = __i;
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+bool
+__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    switch (__last - __first)
+    {
+    case 0:
+    case 1:
+        return true;
+    case 2:
+        if (__comp(*--__last, *__first))
+            swap(*__first, *__last);
+        return true;
+    case 3:
+        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
+        return true;
+    case 4:
+        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
+        return true;
+    case 5:
+        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
+        return true;
+    }
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    _RandomAccessIterator __j = __first+2;
+    __sort3<_Compare>(__first, __first+1, __j, __comp);
+    const unsigned __limit = 8;
+    unsigned __count = 0;
+    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__j))
+        {
+            value_type __t(_VSTD::move(*__i));
+            _RandomAccessIterator __k = __j;
+            __j = __i;
+            do
+            {
+                *__j = _VSTD::move(*__k);
+                __j = __k;
+            } while (__j != __first && __comp(__t, *--__k));
+            *__j = _VSTD::move(__t);
+            if (++__count == __limit)
+                return ++__i == __last;
+        }
+        __j = __i;
+    }
+    return true;
+}
+
+template <class _Compare, class _BirdirectionalIterator>
+void
+__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
+                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
+{
+    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
+    if (__first1 != __last1)
+    {
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
+        value_type* __last2 = __first2;
+        ::new(__last2) value_type(_VSTD::move(*__first1));
+        __d.__incr((value_type*)0);
+        for (++__last2; ++__first1 != __last1; ++__last2)
+        {
+            value_type* __j2 = __last2;
+            value_type* __i2 = __j2;
+            if (__comp(*__first1, *--__i2))
+            {
+                ::new(__j2) value_type(_VSTD::move(*__i2));
+                __d.__incr((value_type*)0);
+                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
+                    *__j2 = _VSTD::move(*__i2);
+                *__j2 = _VSTD::move(*__first1);
+            }
+            else
+            {
+                ::new(__j2) value_type(_VSTD::move(*__first1));
+                __d.__incr((value_type*)0);
+            }
+        }
+        __h.release();
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    // _Compare is known to be a reference type
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
+                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
+    while (true)
+    {
+    __restart:
+        difference_type __len = __last - __first;
+        switch (__len)
+        {
+        case 0:
+        case 1:
+            return;
+        case 2:
+            if (__comp(*--__last, *__first))
+                swap(*__first, *__last);
+            return;
+        case 3:
+            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
+            return;
+        case 4:
+            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
+            return;
+        case 5:
+            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
+            return;
+        }
+        if (__len <= __limit)
+        {
+            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
+            return;
+        }
+        // __len > 5
+        _RandomAccessIterator __m = __first;
+        _RandomAccessIterator __lm1 = __last;
+        --__lm1;
+        unsigned __n_swaps;
+        {
+        difference_type __delta;
+        if (__len >= 1000)
+        {
+            __delta = __len/2;
+            __m += __delta;
+            __delta /= 2;
+            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
+        }
+        else
+        {
+            __delta = __len/2;
+            __m += __delta;
+            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
+        }
+        }
+        // *__m is median
+        // partition [__first, __m) < *__m and *__m <= [__m, __last)
+        // (this inhibits tossing elements equivalent to __m around unnecessarily)
+        _RandomAccessIterator __i = __first;
+        _RandomAccessIterator __j = __lm1;
+        // j points beyond range to be tested, *__m is known to be <= *__lm1
+        // The search going up is known to be guarded but the search coming down isn't.
+        // Prime the downward search with a guard.
+        if (!__comp(*__i, *__m))  // if *__first == *__m
+        {
+            // *__first == *__m, *__first doesn't go in first part
+            // manually guard downward moving __j against __i
+            while (true)
+            {
+                if (__i == --__j)
+                {
+                    // *__first == *__m, *__m <= all other elements
+                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
+                    ++__i;  // __first + 1
+                    __j = __last;
+                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
+                    {
+                        while (true)
+                        {
+                            if (__i == __j)
+                                return;  // [__first, __last) all equivalent elements
+                            if (__comp(*__first, *__i))
+                            {
+                                swap(*__i, *__j);
+                                ++__n_swaps;
+                                ++__i;
+                                break;
+                            }
+                            ++__i;
+                        }
+                    }
+                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
+                    if (__i == __j)
+                        return;
+                    while (true)
+                    {
+                        while (!__comp(*__first, *__i))
+                            ++__i;
+                        while (__comp(*__first, *--__j))
+                            ;
+                        if (__i >= __j)
+                            break;
+                        swap(*__i, *__j);
+                        ++__n_swaps;
+                        ++__i;
+                    }
+                    // [__first, __i) == *__first and *__first < [__i, __last)
+                    // The first part is sorted, sort the secod part
+                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
+                    __first = __i;
+                    goto __restart;
+                }
+                if (__comp(*__j, *__m))
+                {
+                    swap(*__i, *__j);
+                    ++__n_swaps;
+                    break;  // found guard for downward moving __j, now use unguarded partition
+                }
+            }
+        }
+        // It is known that *__i < *__m
+        ++__i;
+        // j points beyond range to be tested, *__m is known to be <= *__lm1
+        // if not yet partitioned...
+        if (__i < __j)
+        {
+            // known that *(__i - 1) < *__m
+            // known that __i <= __m
+            while (true)
+            {
+                // __m still guards upward moving __i
+                while (__comp(*__i, *__m))
+                    ++__i;
+                // It is now known that a guard exists for downward moving __j
+                while (!__comp(*--__j, *__m))
+                    ;
+                if (__i > __j)
+                    break;
+                swap(*__i, *__j);
+                ++__n_swaps;
+                // It is known that __m != __j
+                // If __m just moved, follow it
+                if (__m == __i)
+                    __m = __j;
+                ++__i;
+            }
+        }
+        // [__first, __i) < *__m and *__m <= [__i, __last)
+        if (__i != __m && __comp(*__m, *__i))
+        {
+            swap(*__i, *__m);
+            ++__n_swaps;
+        }
+        // [__first, __i) < *__i and *__i <= [__i+1, __last)
+        // If we were given a perfect partition, see if insertion sort is quick...
+        if (__n_swaps == 0)
+        {
+            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
+            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
+            {
+                if (__fs)
+                    return;
+                __last = __i;
+                continue;
+            }
+            else
+            {
+                if (__fs)
+                {
+                    __first = ++__i;
+                    continue;
+                }
+            }
+        }
+        // sort smaller range with recursive call and larger with tail recursion elimination
+        if (__i - __first < __last - __i)
+        {
+            _VSTD::__sort<_Compare>(__first, __i, __comp);
+            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
+            __first = ++__i;
+        }
+        else
+        {
+            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
+            // _VSTD::__sort<_Compare>(__first, __i, __comp);
+            __last = __i;
+        }
+    }
+}
+
+// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __sort<_Comp_ref>(__first, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __sort<_Comp_ref>(__first, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort(_Tp** __first, _Tp** __last)
+{
+    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
+{
+    _VSTD::sort(__first.base(), __last.base());
+}
+
+template <class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
+{
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
+}
+
+#ifdef _LIBCPP_MSVC
+#pragma warning( push )
+#pragma warning( disable: 4231)
+#endif // _LIBCPP_MSVC
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&))
+#ifdef _LIBCPP_MSVC
+#pragma warning( pop )
+#endif  // _LIBCPP_MSVC
+
+// lower_bound
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+_ForwardIterator
+__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = __len / 2;
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(*__m, __value_))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else
+            __len = __l2;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::lower_bound(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+// upper_bound
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+_ForwardIterator
+__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = __len / 2;
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(__value_, *__m))
+            __len = __l2;
+        else
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+    }
+    return __first;
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::upper_bound(__first, __last, __value_,
+                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// equal_range
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+pair<_ForwardIterator, _ForwardIterator>
+__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = __len / 2;
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(*__m, __value_))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else if (__comp(__value_, *__m))
+        {
+            __last = __m;
+            __len = __l2;
+        }
+        else
+        {
+            _ForwardIterator __mp1 = __m;
+            return pair<_ForwardIterator, _ForwardIterator>
+                   (
+                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
+                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
+                   );
+        }
+    }
+    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::equal_range(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+// binary_search
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
+    return __first != __last && !__comp(__value_, *__first);
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::binary_search(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+// merge
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_OutputIterator
+__merge(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = *__first2;
+            ++__first2;
+        }
+        else
+        {
+            *__result = *__first1;
+            ++__first1;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
+}
+
+// inplace_merge
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::pointer pointer;
+    __destruct_n __d(0);
+    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
+    if (__len1 <= __len2)
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), ++__i, ++__p)
+            ::new(__p) value_type(_VSTD::move(*__i));
+        __merge<_Compare>(move_iterator<value_type*>(__buff),
+                          move_iterator<value_type*>(__p),
+                          move_iterator<_BidirectionalIterator>(__middle),
+                          move_iterator<_BidirectionalIterator>(__last),
+                          __first, __comp);
+    }
+    else
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), ++__i, ++__p)
+            ::new(__p) value_type(_VSTD::move(*__i));
+        typedef reverse_iterator<_BidirectionalIterator> _RBi;
+        typedef reverse_iterator<value_type*> _Rv;
+        __merge(move_iterator<_RBi>(_RBi(__middle)), move_iterator<_RBi>(_RBi(__first)),
+                move_iterator<_Rv>(_Rv(__p)), move_iterator<_Rv>(_Rv(__buff)),
+                _RBi(__last), __negate<_Compare>(__comp));
+    }
+}
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    while (true)
+    {
+        // if __middle == __last, we're done
+        if (__len2 == 0)
+            return;
+        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
+        for (; true; ++__first, --__len1)
+        {
+            if (__len1 == 0)
+                return;
+            if (__comp(*__middle, *__first))
+                break;
+        }
+        if (__len1 <= __buff_size || __len2 <= __buff_size)
+        {
+            __buffered_inplace_merge<_Compare>(__first, __middle, __last, __comp, __len1, __len2, __buff);
+            return;
+        }
+        // __first < __middle < __last
+        // *__first > *__middle
+        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
+        //     all elements in:
+        //         [__first, __m1)  <= [__middle, __m2)
+        //         [__middle, __m2) <  [__m1, __middle)
+        //         [__m1, __middle) <= [__m2, __last)
+        //     and __m1 or __m2 is in the middle of its range
+        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
+        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
+        difference_type __len11;      // distance(__first, __m1)
+        difference_type __len21;      // distance(__middle, __m2)
+        // binary search smaller range
+        if (__len1 < __len2)
+        {   // __len >= 1, __len2 >= 2
+            __len21 = __len2 / 2;
+            __m2 = __middle;
+            _VSTD::advance(__m2, __len21);
+            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
+            __len11 = _VSTD::distance(__first, __m1);
+        }
+        else
+        {
+            if (__len1 == 1)
+            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
+                // It is known *__first > *__middle
+                swap(*__first, *__middle);
+                return;
+            }
+            // __len1 >= 2, __len2 >= 1
+            __len11 = __len1 / 2;
+            __m1 = __first;
+            _VSTD::advance(__m1, __len11);
+            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
+            __len21 = _VSTD::distance(__middle, __m2);
+        }
+        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
+        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
+        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
+        // swap middle two partitions
+        __middle = _VSTD::rotate(__m1, __middle, __m2);
+        // __len12 and __len21 now have swapped meanings
+        // merge smaller range with recurisve call and larger with tail recursion elimination
+        if (__len11 + __len21 < __len12 + __len22)
+        {
+            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
+//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
+            __first = __middle;
+            __middle = __m2;
+            __len1 = __len12;
+            __len2 = __len22;
+        }
+        else
+        {
+            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
+//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
+            __last = __middle;
+            __middle = __m1;
+            __len1 = __len11;
+            __len2 = __len21;
+        }
+    }
+}
+
+template <class _Tp>
+struct __inplace_merge_switch
+{
+    static const unsigned value = is_trivially_copy_assignable<_Tp>::value;
+};
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+              _Compare __comp)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    difference_type __len1 = _VSTD::distance(__first, __middle);
+    difference_type __len2 = _VSTD::distance(__middle, __last);
+    difference_type __buf_size = _VSTD::min(__len1, __len2);
+    pair<value_type*, ptrdiff_t> __buf(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__inplace_merge_switch<value_type>::value && __buf_size > 8)
+    {
+        __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
+        __h.reset(__buf.first);
+    }
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
+                                            __buf.first, __buf.second);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
+                                            __buf.first, __buf.second);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
+{
+    _VSTD::inplace_merge(__first, __middle, __last,
+                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+// stable_sort
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+void
+__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2,
+        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
+    __destruct_n __d(0);
+    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
+    for (; true; ++__result)
+    {
+        if (__first1 == __last1)
+        {
+            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
+                ::new (__result) value_type(_VSTD::move(*__first2));
+            __h.release();
+            return;
+        }
+        if (__first2 == __last2)
+        {
+            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
+                ::new (__result) value_type(_VSTD::move(*__first1));
+            __h.release();
+            return;
+        }
+        if (__comp(*__first2, *__first1))
+        {
+            ::new (__result) value_type(_VSTD::move(*__first2));
+            __d.__incr((value_type*)0);
+            ++__first2;
+        }
+        else
+        {
+            ::new (__result) value_type(_VSTD::move(*__first1));
+            __d.__incr((value_type*)0);
+            ++__first1;
+        }
+    }
+}
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+void
+__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2,
+        _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+        {
+            for (; __first1 != __last1; ++__first1, ++__result)
+                *__result = _VSTD::move(*__first1);
+            return;
+        }
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = _VSTD::move(*__first2);
+            ++__first2;
+        }
+        else
+        {
+            *__result = _VSTD::move(*__first1);
+            ++__first1;
+        }
+    }
+    for (; __first2 != __last2; ++__first2, ++__result)
+        *__result = _VSTD::move(*__first2);
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
+                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    switch (__len)
+    {
+    case 0:
+        return;
+    case 1:
+        ::new(__first2) value_type(_VSTD::move(*__first1));
+        return;
+    case 2:
+       __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
+         if (__comp(*--__last1, *__first1))
+        {
+            ::new(__first2) value_type(_VSTD::move(*__last1));
+            __d.__incr((value_type*)0);
+            ++__first2;
+            ::new(__first2) value_type(_VSTD::move(*__first1));
+        }
+        else
+        {
+            ::new(__first2) value_type(_VSTD::move(*__first1));
+            __d.__incr((value_type*)0);
+            ++__first2;
+            ::new(__first2) value_type(_VSTD::move(*__last1));
+        }
+        __h2.release();
+        return;
+    }
+    if (__len <= 8)
+    {
+        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
+        return;
+    }
+    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
+    _RandomAccessIterator __m = __first1 + __l2;
+    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
+    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
+    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
+}
+
+template <class _Tp>
+struct __stable_sort_switch
+{
+    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
+};
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    switch (__len)
+    {
+    case 0:
+    case 1:
+        return;
+    case 2:
+        if (__comp(*--__last, *__first))
+            swap(*__first, *__last);
+        return;
+    }
+    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
+    {
+        __insertion_sort<_Compare>(__first, __last, __comp);
+        return;
+    }
+    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
+    _RandomAccessIterator __m = __first + __l2;
+    if (__len <= __buff_size)
+    {
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
+        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
+        __d.__set(__l2, (value_type*)0);
+        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
+        __d.__set(__len, (value_type*)0);
+        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
+//         __merge<_Compare>(move_iterator<value_type*>(__buff),
+//                           move_iterator<value_type*>(__buff + __l2),
+//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
+//                           move_iterator<_RandomAccessIterator>(__buff + __len),
+//                           __first, __comp);
+        return;
+    }
+    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
+    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
+    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __len = __last - __first;
+    pair<value_type*, ptrdiff_t> __buf(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
+    {
+        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__buf.first);
+    }
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// is_heap_until
+
+template <class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __len = __last - __first;
+    difference_type __p = 0;
+    difference_type __c = 1;
+    _RandomAccessIterator __pp = __first;
+    while (__c < __len)
+    {
+        _RandomAccessIterator __cp = __first + __c;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__c;
+        ++__cp;
+        if (__c == __len)
+            return __last;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__p;
+        ++__pp;
+        __c = 2 * __p + 1;
+    }
+    return __last;
+}
+
+template<class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// is_heap
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
+}
+
+template<class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// push_heap
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__push_heap_front(_RandomAccessIterator __first, _RandomAccessIterator, _Compare __comp,
+                  typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    if (__len > 1)
+    {
+        difference_type __p = 0;
+        _RandomAccessIterator __pp = __first;
+        difference_type __c = 2;
+        _RandomAccessIterator __cp = __first + __c;
+        if (__c == __len || __comp(*__cp, *(__cp - 1)))
+        {
+            --__c;
+            --__cp;
+        }
+        if (__comp(*__pp, *__cp))
+        {
+            value_type __t(_VSTD::move(*__pp));
+            do
+            {
+                *__pp = _VSTD::move(*__cp);
+                __pp = __cp;
+                __p = __c;
+                __c = (__p + 1) * 2;
+                if (__c > __len)
+                    break;
+                __cp = __first + __c;
+                if (__c == __len || __comp(*__cp, *(__cp - 1)))
+                {
+                    --__c;
+                    --__cp;
+                }
+            } while (__comp(__t, *__cp));
+            *__pp = _VSTD::move(__t);
+        }
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__push_heap_back(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+                 typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    if (__len > 1)
+    {
+        __len = (__len - 2) / 2;
+        _RandomAccessIterator __ptr = __first + __len;
+        if (__comp(*__ptr, *--__last))
+        {
+            value_type __t(_VSTD::move(*__last));
+            do
+            {
+                *__last = _VSTD::move(*__ptr);
+                __last = __ptr;
+                if (__len == 0)
+                    break;
+                __len = (__len - 1) / 2;
+                __ptr = __first + __len;
+            } while (__comp(*__ptr, __t));
+            *__last = _VSTD::move(__t);
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __push_heap_back<_Comp_ref>(__first, __last, __c, __last - __first);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __push_heap_back<_Comp_ref>(__first, __last, __comp, __last - __first);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// pop_heap
+
+template <class _Compare, class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    if (__len > 1)
+    {
+        swap(*__first, *--__last);
+        __push_heap_front<_Compare>(__first, __last, __comp, __len-1);
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// make_heap
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __n = __last - __first;
+    if (__n > 1)
+    {
+        __last = __first;
+        ++__last;
+        for (difference_type __i = 1; __i < __n;)
+            __push_heap_back<_Compare>(__first, ++__last, __comp, ++__i);
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __make_heap<_Comp_ref>(__first, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __make_heap<_Comp_ref>(__first, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// sort_heap
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
+        __pop_heap<_Compare>(__first, __last, __comp, __n);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __sort_heap<_Comp_ref>(__first, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __sort_heap<_Comp_ref>(__first, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// partial_sort
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+             _Compare __comp)
+{
+    __make_heap<_Compare>(__first, __middle, __comp);
+    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
+    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__first))
+        {
+            swap(*__i, *__first);
+            __push_heap_front<_Compare>(__first, __middle, __comp, __len);
+        }
+    }
+    __sort_heap<_Compare>(__first, __middle, __comp);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+             _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    _VSTD::partial_sort(__first, __middle, __last,
+                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// partial_sort_copy
+
+template <class _Compare, class _InputIterator, class _RandomAccessIterator>
+_RandomAccessIterator
+__partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
+{
+    _RandomAccessIterator __r = __result_first;
+    if (__r != __result_last)
+    {
+        typename iterator_traits<_RandomAccessIterator>::difference_type __len = 0;
+        for (; __first != __last && __r != __result_last; ++__first, ++__r, ++__len)
+            *__r = *__first;
+        __make_heap<_Compare>(__result_first, __r, __comp);
+        for (; __first != __last; ++__first)
+            if (__comp(*__first, *__result_first))
+            {
+                *__result_first = *__first;
+                __push_heap_front<_Compare>(__result_first, __r, __comp, __len);
+            }
+        __sort_heap<_Compare>(__result_first, __r, __comp);
+    }
+    return __r;
+}
+
+template <class _InputIterator, class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator, class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
+{
+    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
+                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// nth_element
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
+{
+    // _Compare is known to be a reference type
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    const difference_type __limit = 7;
+    while (true)
+    {
+    __restart:
+        if (__nth == __last)
+            return;
+        difference_type __len = __last - __first;
+        switch (__len)
+        {
+        case 0:
+        case 1:
+            return;
+        case 2:
+            if (__comp(*--__last, *__first))
+                swap(*__first, *__last);
+            return;
+        case 3:
+            {
+            _RandomAccessIterator __m = __first;
+            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
+            return;
+            }
+        }
+        if (__len <= __limit)
+        {
+            __selection_sort<_Compare>(__first, __last, __comp);
+            return;
+        }
+        // __len > __limit >= 3
+        _RandomAccessIterator __m = __first + __len/2;
+        _RandomAccessIterator __lm1 = __last;
+        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
+        // *__m is median
+        // partition [__first, __m) < *__m and *__m <= [__m, __last)
+        // (this inhibits tossing elements equivalent to __m around unnecessarily)
+        _RandomAccessIterator __i = __first;
+        _RandomAccessIterator __j = __lm1;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // The search going up is known to be guarded but the search coming down isn't.
+        // Prime the downward search with a guard.
+        if (!__comp(*__i, *__m))  // if *__first == *__m
+        {
+            // *__first == *__m, *__first doesn't go in first part
+            // manually guard downward moving __j against __i
+            while (true)
+            {
+                if (__i == --__j)
+                {
+                    // *__first == *__m, *__m <= all other elements
+                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
+                    ++__i;  // __first + 1
+                    __j = __last;
+                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
+                    {
+                        while (true)
+                        {
+                            if (__i == __j)
+                                return;  // [__first, __last) all equivalent elements
+                            if (__comp(*__first, *__i))
+                            {
+                                swap(*__i, *__j);
+                                ++__n_swaps;
+                                ++__i;
+                                break;
+                            }
+                            ++__i;
+                        }
+                    }
+                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
+                    if (__i == __j)
+                        return;
+                    while (true)
+                    {
+                        while (!__comp(*__first, *__i))
+                            ++__i;
+                        while (__comp(*__first, *--__j))
+                            ;
+                        if (__i >= __j)
+                            break;
+                        swap(*__i, *__j);
+                        ++__n_swaps;
+                        ++__i;
+                    }
+                    // [__first, __i) == *__first and *__first < [__i, __last)
+                    // The first part is sorted,
+                    if (__nth < __i)
+                        return;
+                    // __nth_element the secod part
+                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
+                    __first = __i;
+                    goto __restart;
+                }
+                if (__comp(*__j, *__m))
+                {
+                    swap(*__i, *__j);
+                    ++__n_swaps;
+                    break;  // found guard for downward moving __j, now use unguarded partition
+                }
+            }
+        }
+        ++__i;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // if not yet partitioned...
+        if (__i < __j)
+        {
+            // known that *(__i - 1) < *__m
+            while (true)
+            {
+                // __m still guards upward moving __i
+                while (__comp(*__i, *__m))
+                    ++__i;
+                // It is now known that a guard exists for downward moving __j
+                while (!__comp(*--__j, *__m))
+                    ;
+                if (__i >= __j)
+                    break;
+                swap(*__i, *__j);
+                ++__n_swaps;
+                // It is known that __m != __j
+                // If __m just moved, follow it
+                if (__m == __i)
+                    __m = __j;
+                ++__i;
+            }
+        }
+        // [__first, __i) < *__m and *__m <= [__i, __last)
+        if (__i != __m && __comp(*__m, *__i))
+        {
+            swap(*__i, *__m);
+            ++__n_swaps;
+        }
+        // [__first, __i) < *__i and *__i <= [__i+1, __last)
+        if (__nth == __i)
+            return;
+        if (__n_swaps == 0)
+        {
+            // We were given a perfectly partitioned sequence.  Coincidence?
+            if (__nth < __i)
+            {
+                // Check for [__first, __i) already sorted
+                __j = __m = __first;
+                while (++__j != __i)
+                {
+                    if (__comp(*__j, *__m))
+                        // not yet sorted, so sort
+                        goto not_sorted;
+                    __m = __j;
+                }
+                // [__first, __i) sorted
+                return;
+            }
+            else
+            {
+                // Check for [__i, __last) already sorted
+                __j = __m = __i;
+                while (++__j != __last)
+                {
+                    if (__comp(*__j, *__m))
+                        // not yet sorted, so sort
+                        goto not_sorted;
+                    __m = __j;
+                }
+                // [__i, __last) sorted
+                return;
+            }
+        }
+not_sorted:
+        // __nth_element on range containing __nth
+        if (__nth < __i)
+        {
+            // __nth_element<_Compare>(__first, __nth, __i, __comp);
+            __last = __i;
+        }
+        else
+        {
+            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
+            __first = ++__i;
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
+{
+    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+// includes
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+bool
+__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+           _Compare __comp)
+{
+    for (; __first2 != __last2; ++__first1)
+    {
+        if (__first1 == __last1 || __comp(*__first2, *__first1))
+            return false;
+        if (!__comp(*__first1, *__first2))
+            ++__first2;
+    }
+    return true;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+         _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    return _VSTD::includes(__first1, __last1, __first2, __last2,
+                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// set_union
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_OutputIterator
+__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = *__first2;
+            ++__first2;
+        }
+        else
+        {
+            *__result = *__first1;
+            if (!__comp(*__first1, *__first2))
+                ++__first2;
+            ++__first1;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
+                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// set_intersection
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_OutputIterator
+__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1 && __first2 != __last2)
+    {
+        if (__comp(*__first1, *__first2))
+            ++__first1;
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+            {
+                *__result = *__first1;
+                ++__result;
+                ++__first1;
+            }
+            ++__first2;
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
+                                  __less<typename iterator_traits<_InputIterator1>::value_type,
+                                         typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// set_difference
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_OutputIterator
+__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first1, *__first2))
+        {
+            *__result = *__first1;
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
+                                __less<typename iterator_traits<_InputIterator1>::value_type,
+                                       typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// set_symmetric_difference
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_OutputIterator
+__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first1, *__first2))
+        {
+            *__result = *__first1;
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (__comp(*__first2, *__first1))
+            {
+                *__result = *__first2;
+                ++__result;
+            }
+            else
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
+                                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// lexicographical_compare
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+bool
+__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+    for (; __first2 != __last2; ++__first1, ++__first2)
+    {
+        if (__first1 == __last1 || __comp(*__first1, *__first2))
+            return true;
+        if (__comp(*__first2, *__first1))
+            return false;
+    }
+    return false;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
+                                         __less<typename iterator_traits<_InputIterator1>::value_type,
+                                                typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+// next_permutation
+
+template <class _Compare, class _BidirectionalIterator>
+bool
+__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    _BidirectionalIterator __i = __last;
+    if (__first == __last || __first == --__i)
+        return false;
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*--__i, *__ip1))
+        {
+            _BidirectionalIterator __j = __last;
+            while (!__comp(*__i, *--__j))
+                ;
+            swap(*__i, *__j);
+            _VSTD::reverse(__ip1, __last);
+            return true;
+        }
+        if (__i == __first)
+        {
+            _VSTD::reverse(__first, __last);
+            return false;
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __next_permutation<_Comp_ref>(__first, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __next_permutation<_Comp_ref>(__first, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::next_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+// prev_permutation
+
+template <class _Compare, class _BidirectionalIterator>
+bool
+__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    _BidirectionalIterator __i = __last;
+    if (__first == __last || __first == --__i)
+        return false;
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*__ip1, *--__i))
+        {
+            _BidirectionalIterator __j = __last;
+            while (!__comp(*--__j, *__i))
+                ;
+            swap(*__i, *__j);
+            _VSTD::reverse(__ip1, __last);
+            return true;
+        }
+        if (__i == __first)
+        {
+            _VSTD::reverse(__first, __last);
+            return false;
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+#ifdef _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
+    __debug_less<_Compare> __c(__comp);
+    return __prev_permutation<_Comp_ref>(__first, __last, __c);
+#else  // _LIBCPP_DEBUG
+    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
+    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
+#endif  // _LIBCPP_DEBUG
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::prev_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value,
+    _Tp
+>::type
+__rotate_left(_Tp __t, _Tp __n = 1)
+{
+    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
+    __n &= __bits;
+    return static_cast<_Tp>((__t << __n) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> (__bits - __n)));
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value,
+    _Tp
+>::type
+__rotate_right(_Tp __t, _Tp __n = 1)
+{
+    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
+    __n &= __bits;
+    return static_cast<_Tp>((__t << (__bits - __n)) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> __n));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP_ALGORITHM