How do I use the std::priority_queue in C++11?

How do I use the std::priority_queue in C++11?

The std::priority_queue in C++11 is a container adaptor that provides a way to maintain a collection of elements in a specific order. It allows you to efficiently access the largest (or smallest) element. Would you like a code example?

Yes, please provide a code example.

Here's a simple example:

#include <iostream>
#include <queue>

int main() {
    std::priority_queue<int> pq;
    pq.push(10);
    pq.push(30);
    pq.push(20);

    std::cout << "Top element: " << pq.top() << std::endl; // Outputs 30
    pq.pop();
    std::cout << "Next top element: " << pq.top() << std::endl; // Outputs 20
    return 0;
}

This code demonstrates how to push elements into the priority queue and access the top element.

What if I want to use a custom comparator?

You can define a custom comparator by creating a struct or a lambda function. Here's an example using a lambda:

auto cmp = [](int left, int right) { return left > right; };
std::priority_queue<int, std::vector<int>, decltype(cmp)> pq(cmp);

This will create a min-heap instead of a max-heap.

Can I use std::priority_queue with other data types?

Yes, you can use std::priority_queue with any data type, including custom structs or classes, as long as you provide a comparator for ordering.