| Index: packages/collection/lib/priority_queue.dart
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| diff --git a/packages/collection/lib/priority_queue.dart b/packages/collection/lib/priority_queue.dart
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| index e1a01777119884731eb24b2dc0aa9cc161225490..f2a4703e19be5166ea93574977e9e5c755e9da0b 100644
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| --- a/packages/collection/lib/priority_queue.dart
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| +++ b/packages/collection/lib/priority_queue.dart
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| @@ -2,395 +2,8 @@
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| // for details. All rights reserved. Use of this source code is governed by a
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| // BSD-style license that can be found in the LICENSE file.
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|
|
| +/// Import `collection.dart` instead.
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| +@Deprecated("Will be removed in collection 2.0.0.")
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| library dart.pkg.collection.priority_queue;
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|
|
| -import "dart:collection" show SplayTreeSet;
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| -
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| -/**
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| - * A priority queue is a priority based work-list of elements.
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| - *
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| - * The queue allows adding elements, and removing them again in priority order.
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| - */
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| -abstract class PriorityQueue<E> {
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| - /**
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| - * Number of elements in the queue.
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| - */
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| - int get length;
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| -
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| - /**
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| - * Whether the queue is empty.
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| - */
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| - bool get isEmpty;
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| -
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| - /**
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| - * Whether the queue has any elements.
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| - */
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| - bool get isNotEmpty;
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| -
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| - /**
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| - * Checks if [object] is in the queue.
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| - *
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| - * Returns true if the element is found.
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| - */
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| - bool contains(E object);
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| -
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| - /**
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| - * Adds element to the queue.
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| - *
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| - * The element will become the next to be removed by [removeFirst]
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| - * when all elements with higher priority have been removed.
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| - */
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| - void add(E element);
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| -
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| - /**
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| - * Adds all [elements] to the queue.
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| - */
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| - void addAll(Iterable<E> elements);
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| -
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| - /**
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| - * Returns the next element that will be returned by [removeFirst].
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| - *
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| - * The element is not removed from the queue.
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| - *
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| - * The queue must not be empty when this method is called.
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| - */
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| - E get first;
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| -
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| - /**
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| - * Removes and returns the element with the highest priority.
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| - *
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| - * Repeatedly calling this method, without adding element in between,
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| - * is guaranteed to return elements in non-decreasing order as, specified by
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| - * [comparison].
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| - *
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| - * The queue must not be empty when this method is called.
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| - */
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| - E removeFirst();
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| -
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| - /**
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| - * Removes an element that compares equal to [element] in the queue.
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| - *
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| - * Returns true if an element is found and removed,
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| - * and false if no equal element is found.
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| - */
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| - bool remove(E element);
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| -
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| - /**
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| - * Removes all the elements from this queue and returns them.
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| - *
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| - * The returned iterable has no specified order.
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| - */
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| - Iterable<E> removeAll();
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| -
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| - /**
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| - * Removes all the elements from this queue.
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| - */
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| - void clear();
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| -
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| - /**
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| - * Returns a list of the elements of this queue in priority order.
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| - *
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| - * The queue is not modified.
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| - *
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| - * The order is the order that the elements would be in if they were
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| - * removed from this queue using [removeFirst].
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| - */
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| - List<E> toList();
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| -
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| - /**
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| - * Return a comparator based set using the comparator of this queue.
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| - *
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| - * The queue is not modified.
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| - *
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| - * The returned [Set] is currently a [SplayTreeSet],
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| - * but this may change as other ordered sets are implemented.
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| - *
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| - * The set contains all the elements of this queue.
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| - * If an element occurs more than once in the queue,
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| - * the set will contain it only once.
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| - */
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| - Set<E> toSet();
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| -}
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| -
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| -/**
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| - * Heap based priority queue.
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| - *
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| - * The elements are kept in a heap structure,
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| - * where the element with the highest priority is immediately accessible,
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| - * and modifying a single element takes
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| - * logarithmic time in the number of elements on average.
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| - *
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| - * * The [add] and [removeFirst] operations take amortized logarithmic time,
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| - * O(log(n)), but may occasionally take linear time when growing the capacity
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| - * of the heap.
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| - * * The [addAll] operation works as doing repeated [add] operations.
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| - * * The [first] getter takes constant time, O(1).
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| - * * The [clear] and [removeAll] methods also take constant time, O(1).
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| - * * The [contains] and [remove] operations may need to search the entire
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| - * queue for the elements, taking O(n) time.
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| - * * The [toList] operation effectively sorts the elements, taking O(n*log(n))
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| - * time.
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| - * * The [toSet] operation effectively adds each element to the new set, taking
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| - * an expected O(n*log(n)) time.
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| - */
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| -class HeapPriorityQueue<E> implements PriorityQueue<E> {
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| - /**
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| - * Initial capacity of a queue when created, or when added to after a [clear].
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| - *
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| - * Number can be any positive value. Picking a size that gives a whole
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| - * number of "tree levels" in the heap is only done for aesthetic reasons.
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| - */
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| - static const int _INITIAL_CAPACITY = 7;
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| -
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| - /**
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| - * The comparison being used to compare the priority of elements.
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| - */
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| - final Comparator comparison;
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| -
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| - /**
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| - * List implementation of a heap.
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| - */
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| - List<E> _queue = new List<E>(_INITIAL_CAPACITY);
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| -
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| - /**
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| - * Number of elements in queue.
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| - *
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| - * The heap is implemented in the first [_length] entries of [_queue].
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| - */
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| - int _length = 0;
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| -
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| - /**
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| - * Create a new priority queue.
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| - *
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| - * The [comparison] is a [Comparator] used to compare the priority of
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| - * elements. An element that compares as less than another element has
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| - * a higher priority.
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| - *
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| - * If [comparison] is omitted, it defaults to [Comparable.compare].
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| - */
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| - HeapPriorityQueue([int comparison(E e1, E e2)])
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| - : comparison = (comparison != null) ? comparison : Comparable.compare;
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| -
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| - void add(E element) {
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| - _add(element);
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| - }
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| -
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| - void addAll(Iterable<E> elements) {
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| - for (E element in elements) {
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| - _add(element);
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| - }
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| - }
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| -
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| - void clear() {
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| - _queue = const [];
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| - _length = 0;
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| - }
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| -
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| - bool contains(E object) {
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| - return _locate(object) >= 0;
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| - }
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| -
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| - E get first {
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| - if (_length == 0) throw new StateError("No such element");
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| - return _queue[0];
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| - }
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| -
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| - bool get isEmpty => _length == 0;
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| -
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| - bool get isNotEmpty => _length != 0;
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| -
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| - int get length => _length;
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| -
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| - bool remove(E element) {
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| - int index = _locate(element);
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| - if (index < 0) return false;
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| - E last = _removeLast();
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| - if (index < _length) {
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| - int comp = comparison(last, element);
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| - if (comp <= 0) {
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| - _bubbleUp(last, index);
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| - } else {
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| - _bubbleDown(last, index);
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| - }
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| - }
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| - return true;
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| - }
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| -
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| - Iterable<E> removeAll() {
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| - List<E> result = _queue;
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| - int length = _length;
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| - _queue = const [];
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| - _length = 0;
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| - return result.take(length);
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| - }
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| -
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| - E removeFirst() {
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| - if (_length == 0) throw new StateError("No such element");
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| - E result = _queue[0];
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| - E last = _removeLast();
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| - if (_length > 0) {
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| - _bubbleDown(last, 0);
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| - }
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| - return result;
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| - }
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| -
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| - List<E> toList() {
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| - List<E> list = new List<E>()..length = _length;
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| - list.setRange(0, _length, _queue);
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| - list.sort(comparison);
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| - return list;
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| - }
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| -
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| - Set<E> toSet() {
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| - Set<E> set = new SplayTreeSet<E>(comparison);
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| - for (int i = 0; i < _length; i++) {
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| - set.add(_queue[i]);
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| - }
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| - return set;
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| - }
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| -
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| - /**
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| - * Returns some representation of the queue.
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| - *
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| - * The format isn't significant, and may change in the future.
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| - */
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| - String toString() {
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| - return _queue.take(_length).toString();
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| - }
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| -
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| - /**
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| - * Add element to the queue.
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| - *
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| - * Grows the capacity if the backing list is full.
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| - */
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| - void _add(E element) {
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| - if (_length == _queue.length) _grow();
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| - _bubbleUp(element, _length++);
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| - }
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| -
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| - /**
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| - * Find the index of an object in the heap.
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| - *
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| - * Returns -1 if the object is not found.
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| - */
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| - int _locate(E object) {
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| - if (_length == 0) return -1;
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| - // Count positions from one instead of zero. This gives the numbers
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| - // some nice properties. For example, all right children are odd,
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| - // their left sibling is even, and the parent is found by shifting
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| - // right by one.
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| - // Valid range for position is [1.._length], inclusive.
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| - int position = 1;
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| - // Pre-order depth first search, omit child nodes if the current
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| - // node has lower priority than [object], because all nodes lower
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| - // in the heap will also have lower priority.
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| - do {
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| - int index = position - 1;
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| - E element = _queue[index];
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| - int comp = comparison(element, object);
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| - if (comp == 0) return index;
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| - if (comp < 0) {
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| - // Element may be in subtree.
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| - // Continue with the left child, if it is there.
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| - int leftChildPosition = position * 2;
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| - if (leftChildPosition <= _length) {
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| - position = leftChildPosition;
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| - continue;
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| - }
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| - }
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| - // Find the next right sibling or right ancestor sibling.
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| - do {
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| - while (position.isOdd) {
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| - // While position is a right child, go to the parent.
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| - position >>= 1;
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| - }
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| - // Then go to the right sibling of the left-child.
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| - position += 1;
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| - } while (position > _length); // Happens if last element is a left child.
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| - } while (position != 1); // At root again. Happens for right-most element.
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| - return -1;
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| - }
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| -
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| - E _removeLast() {
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| - int newLength = _length - 1;
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| - E last = _queue[newLength];
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| - _queue[newLength] = null;
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| - _length = newLength;
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| - return last;
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| - }
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| -
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| - /**
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| - * Place [element] in heap at [index] or above.
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| - *
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| - * Put element into the empty cell at `index`.
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| - * While the `element` has higher priority than the
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| - * parent, swap it with the parent.
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| - */
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| - void _bubbleUp(E element, int index) {
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| - while (index > 0) {
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| - int parentIndex = (index - 1) ~/ 2;
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| - E parent = _queue[parentIndex];
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| - if (comparison(element, parent) > 0) break;
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| - _queue[index] = parent;
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| - index = parentIndex;
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| - }
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| - _queue[index] = element;
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| - }
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| -
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| - /**
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| - * Place [element] in heap at [index] or above.
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| - *
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| - * Put element into the empty cell at `index`.
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| - * While the `element` has lower priority than either child,
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| - * swap it with the highest priority child.
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| - */
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| - void _bubbleDown(E element, int index) {
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| - int rightChildIndex = index * 2 + 2;
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| - while (rightChildIndex < _length) {
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| - int leftChildIndex = rightChildIndex - 1;
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| - E leftChild = _queue[leftChildIndex];
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| - E rightChild = _queue[rightChildIndex];
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| - int comp = comparison(leftChild, rightChild);
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| - int minChildIndex;
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| - E minChild;
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| - if (comp < 0) {
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| - minChild = leftChild;
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| - minChildIndex = leftChildIndex;
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| - } else {
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| - minChild = rightChild;
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| - minChildIndex = rightChildIndex;
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| - }
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| - comp = comparison(element, minChild);
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| - if (comp <= 0) {
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| - _queue[index] = element;
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| - return;
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| - }
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| - _queue[index] = minChild;
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| - index = minChildIndex;
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| - rightChildIndex = index * 2 + 2;
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| - }
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| - int leftChildIndex = rightChildIndex - 1;
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| - if (leftChildIndex < _length) {
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| - E child = _queue[leftChildIndex];
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| - int comp = comparison(element, child);
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| - if (comp > 0) {
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| - _queue[index] = child;
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| - index = leftChildIndex;
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| - }
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| - }
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| - _queue[index] = element;
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| - }
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| -
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| - /**
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| - * Grows the capacity of the list holding the heap.
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| - *
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| - * Called when the list is full.
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| - */
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| - void _grow() {
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| - int newCapacity = _queue.length * 2 + 1;
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| - if (newCapacity < _INITIAL_CAPACITY) newCapacity = _INITIAL_CAPACITY;
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| - List<E> newQueue = new List<E>(newCapacity);
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| - newQueue.setRange(0, _length, _queue);
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| - _queue = newQueue;
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| - }
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| -}
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| +export "src/priority_queue.dart";
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|
|