c++11 standard template (STL) (std::priority_queue) (1)

Adapt a container to provide a priority queue

std::priority_queue

Defined in the header file <queue>

template<

class T,
class Container = std::vector<T>,
class Compare = std::less<typename Container::value_type>

> class priority_queue;

priority_queue is a container adapter that provides constant-time (default) maximum element lookup, logarithmic cost insertion and extraction.

The order can be Comparechanged , eg with std::greater<T> will cause the smallest element to appear as top().

priority_queueWorks similarly to managing the heap in some random-access container, with the advantage that it is impossible to suddenly invalidate the heap.

template parameter

T - The stored element type. The behavior is undefined if Tand Container::value_typeis not the same type. (since C++17)

Container

The underlying container type used to store elements. A container must meet the requirements of a sequence container (SequenceContainer), and its iterator must meet the requirements of a legacy random access iterator (LegacyRandomAccessIterator). Additionally, it must provide the following functions with the usual semantics:

front()
push_back()
pop_back()

The standard containers std::vector and std::deque meet these requirements.

Compare - Provides a strict and weakly ordered comparison (Compare) type.

Note that the Compare parameter is defined such that it returns true if its first argument precedes its second argument in weak ordering. But because priority_queue outputs the largest element first, the "first come" element is actually output last. That is, the head of the queue contains the "last" element in the weak ordering imposed by Compare.

member type


member type	definition
`container_type`	`Container`
`value_compare` (C++17)	`Compare`
`value_type`	`Container::value_type`
`size_type`	`Container::size_type`
`reference`	`Container::reference`
`const_reference`	`Container::const_reference`

member function

(Constructor)	Construct `priority_queue` (public member function)
(destructor)	Destructor `priority_queue` (public member function)
operator=	Assign to container adapter (public member function)
element access
top	Access the top element of the stack (public member function)
capacity
empty	Check if the underlying container is empty (public member function)
size	Returns the number of elements held (public member function)
modifier
push	Inserts elements and sorts the underlying container (public member function)
place (C++11)	Constructs elements in-place and sorts the underlying container (public member function)
pop	Delete the top element of the stack (public member function)
swap	exchange content (public member function)
member object
Container c	underlying container (protected member object)
Compare comp	comparison function object (protected member object)

non-member function

std::swap(std::priority_queue)

specialization of the std::swap algorithm
(function template)

Auxiliary class

std::uses_allocator<std::priority_queue>

(C++11)

特化 std::uses_allocator 类型特性
(函数模板)