How to Delete an Element from a Priority Queue in C++ ?

In C++, a priority queue is a queue in which elements are arranged based on their priority values as each element has a priority value associated with it. In this article, we will learn how to delete an element from a priority queue in C++.

For Example,

Input:
myPriorityQueue = {8, 6, 7, 5, 4, 2, 3}

Output:
myPriorityQueue = {7, 6, 3, 5, 4, 2}

Remove Element from Priority Queue in C++

To remove an element from a priority_queue we can use a std::priority_queue::pop() function that directly removes the element with the highest priority (topmost element) from the queue and the element with the next highest priority becomes the top element after deletion.

C++ Program to Delete Element from Priority Queue

The below example demonstrates the deletion of an element using pop() in a priority queue.

// C++ program to delete an element from priority queue
#include <iostream>
#include <queue>

using namespace std;

int main()
{
    // creating a priority queue
    priority_queue<int> pq;
    // push element in a priority queue
    pq.push(10);
    pq.push(30);
    pq.push(20);
    pq.push(50);

    // printing the top most element before deletion
    cout << "Top element before removal: " << pq.top()
         << endl;
    // Remove the top element
    pq.pop();
    // printing the top most element after deletion
    cout << "Top element after removal: " << pq.top()
         << endl;

    return 0;
}

Top element before removal: 50
Top element after removal: 30

Time Complexity: O(log N), where N is the number of elements in the priority queue.
Auxiliary Space: O(1)