The document discusses the C++ Standard Template Library priority queue, which provides constant-time access to the largest or smallest element while maintaining the heap property. A priority queue is a container adaptor that uses a heap to provide efficient insertion and extraction, allowing O(1) retrieval of the maximum or minimum element through top() and removal of the top element using pop(). It can be configured as a max or min heap using different comparators.

1. Level up your coding skills with
the C++ Standard Template
Library (STL):
Priority Queue
BY JOYJIT CHOUDHURY

2. Priority Queue
 A priority_queue is a container adaptor that provides
constant time lookup of the largest (by default) element,
at the expense of logarithmic insertion and extraction.
 A user-provided compare can be supplied to change the
ordering of the elements
 Defined in the header <queue>
 Belongs to the namespace std
(remember : using namespace std)

3. Heap
 priority_queue gives a programmer the functionality of a
heap implemented in the C++ Standard Library
 By default it’s a Max Heap : O(1) lookup of the largest
element
 Using std::greater<int> as Compare makes it
a Min Heap: O(1) lookup of the smallest element

4. Insertion of elements
 push(), inserts a new element in the priority_queue.

5. Access the Top element
 top() returns a constant reference to the top element in the
priority_queue, in constant time

6. Remove the Top element
 pop() removes the top element from the priority_queue,
reducing it’s size by one.

7. Size
 size() returns the number of elements in the priority_queue

8. Is it empty?
 empty() returns true if the priority_queue is empty, else
returns false

11.  That’s not all. There are many other functions
and techniques that could come in handy.
Read about them on cplusplus.com or
cppreference.com or somewhere else. Just
google it !