Any sequence container with random access iterator and supporting operations
front(),
push_back()
and
pop_back()
can be used to instantiate
priority_queue.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>;
template<class T, class Container, class Compare>
void swap(priority_queue<T, Container, Compare>& x,
priority_queue<T, Container, Compare>& y) noexcept(noexcept(x.swap(y)));
template<class T, class Container, class Compare, class Alloc>
struct uses_allocator<priority_queue<T, Container, Compare>, Alloc>
: uses_allocator<Container, Alloc>::type { };
}