3.) Priority Queue (basic)

 Write a program to check if priority queue is empty or not.

import java.util.*;

public class PriorityQueueIsEmptyExample {

    public static void main(String[] args) {

        // Create a priority queue

        PriorityQueue<Integer> pq = new PriorityQueue<>();

        // Check if the priority queue is empty

        if (pq.isEmpty()) {

            System.out.println("The priority queue is empty.");

        } else {

            System.out.println("The priority queue is not empty.");

        }

        // Add some elements to the priority queue

        pq.add(5);

        pq.add(2);

        pq.add(10);

        pq.add(7);

        // Check if the priority queue is empty again

        if (pq.isEmpty()) {

            System.out.println("The priority queue is empty.");

        } else {

            System.out.println("The priority queue is not empty.");

        }

    }

}