Editing Priority queue (section)

== Libraries ==

A priority queue is often considered to be a "[[container (abstract data type)|container data structure]]".

The [[Standard Template Library]] (STL), and the [[C++]] 1998 standard, specifies [https://en.cppreference.com/w/cpp/container/priority_queue std::priority_queue] as one of the STL [[container (programming)|container]] [[adaptor (programming)|adaptor]] [[Template (programming)|class template]]s. However, it does not specify how two elements with same priority should be served, and indeed, common implementations will not return them according to their order in the queue. It implements a max-priority-queue, and has three parameters: a comparison object for sorting such as a function object (defaults to less<T> if unspecified), the underlying container for storing the data structures (defaults to std::vector<T>), and two iterators to the beginning and end of a sequence. Unlike actual STL containers, it does not allow [[Iterator|iteration]] of its elements (it strictly adheres to its abstract data type definition). STL also has utility functions for manipulating another random-access container as a binary max-heap. The [[Boost (C++ libraries)|Boost libraries]] also have an implementation in the library heap.

Python's [https://docs.python.org/library/heapq.html heapq] module implements a binary min-heap on top of a list.

[[Java (programming language)|Java]]'s library contains a {{Javadoc:SE|java/util|PriorityQueue}} class, which implements a min-priority-queue as a binary heap.

[[.NET]]'s library contains a [https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.priorityqueue-2?view=net-6.0 PriorityQueue] class, which implements an array-backed, quaternary min-heap.

[[Scala (programming language)|Scala]]'s library contains a [https://www.scala-lang.org/api/current/scala/collection/mutable/PriorityQueue.html PriorityQueue] class, which implements a max-priority-queue.

[[Go (programming language)|Go]]'s library contains a [http://golang.org/pkg/container/heap/ container/heap] module, which implements a min-heap on top of any compatible data structure.

The [[Standard PHP Library]] extension contains the class [http://us2.php.net/manual/en/class.splpriorityqueue.php SplPriorityQueue].

Apple's [[Core Foundation]] framework contains a [https://developer.apple.com/library/mac/#documentation/CoreFoundation/Reference/CFBinaryHeapRef/Reference/reference.html CFBinaryHeap] structure, which implements a min-heap.