22 Containers library [containers]

22.6 Container adaptors [container.adaptors]

22.6.5 Class template priority_­queue [priority.queue]

22.6.5.1 Overview [priqueue.overview]

Any sequence container with random access iterator and supporting operations front(), push_­back() and pop_­back() can be used to instantiate priority_­queue.
In particular, vector and deque can be used.
Instantiating priority_­queue also involves supplying a function or function object for making priority comparisons; the library assumes that the function or function object defines a strict weak ordering.
namespace std { template<class T, class Container = vector<T>, class Compare = less<typename Container::value_type>> class priority_queue { public: using value_type = typename Container::value_type; using reference = typename Container::reference; using const_reference = typename Container::const_reference; using size_type = typename Container::size_type; using container_type = Container; using value_compare = Compare; protected: Container c; Compare comp; public: priority_queue() : priority_queue(Compare()) {} explicit priority_queue(const Compare& x) : priority_queue(x, Container()) {} priority_queue(const Compare& x, const Container&); priority_queue(const Compare& x, Container&&); template<class InputIterator> priority_queue(InputIterator first, InputIterator last, const Compare& x, const Container&); template<class InputIterator> priority_queue(InputIterator first, InputIterator last, const Compare& x = Compare(), Container&& = Container()); template<class Alloc> explicit priority_queue(const Alloc&); template<class Alloc> priority_queue(const Compare&, const Alloc&); template<class Alloc> priority_queue(const Compare&, const Container&, const Alloc&); template<class Alloc> priority_queue(const Compare&, Container&&, const Alloc&); template<class Alloc> priority_queue(const priority_queue&, const Alloc&); template<class Alloc> priority_queue(priority_queue&&, const Alloc&); [[nodiscard]] bool empty() const { return c.empty(); } size_type size() const { return c.size(); } const_reference top() const { return c.front(); } void push(const value_type& x); void push(value_type&& x); template<class... Args> void emplace(Args&&... args); void pop(); void swap(priority_queue& q) noexcept(is_nothrow_swappable_v<Container> && is_nothrow_swappable_v<Compare>) { using std::swap; swap(c, q.c); swap(comp, q.comp); } }; template<class Compare, class Container> priority_queue(Compare, Container) -> priority_queue<typename Container::value_type, Container, Compare>; template<class InputIterator, class Compare = less<typename iterator_traits<InputIterator>::value_type>, class Container = vector<typename iterator_traits<InputIterator>::value_type>> priority_queue(InputIterator, InputIterator, Compare = Compare(), Container = Container()) -> priority_queue<typename iterator_traits<InputIterator>::value_type, Container, Compare>; template<class Compare, class Container, class Allocator> priority_queue(Compare, Container, Allocator) -> priority_queue<typename Container::value_type, Container, Compare>; // no equality is provided template<class T, class Container, class Compare, class Alloc> struct uses_allocator<priority_queue<T, Container, Compare>, Alloc> : uses_allocator<Container, Alloc>::type { }; }