What are some examples of priority queues in Java?

What are some examples of priority queues in Java?

In Java, a priority queue is a data structure that stores elements in a way that allows for efficient retrieval of the highest (or lowest) priority element. Would you like to see some code examples?

Yes, please provide a code example of a priority queue.

Here's a simple example:

import java.util.PriorityQueue;

public class Main {
    public static void main(String[] args) {
        PriorityQueue<Integer> pq = new PriorityQueue<>();
        pq.add(10);
        pq.add(20);
        pq.add(15);

        System.out.println("Priority Queue: " + pq);
        System.out.println("Poll: " + pq.poll()); // Retrieves and removes the head of the queue
        System.out.println("After Poll: " + pq);
    }
}

This code demonstrates adding elements to a priority queue and retrieving the highest priority element.

What is the output of this code?

The output will be:

Priority Queue: [10, 20, 15]
Poll: 10
After Poll: [15, 20]

The number '10' is removed because it has the highest priority (lowest value) in this case.

Can you explain how the priority is determined in this queue?

In a Java PriorityQueue, the priority is determined by the natural ordering of the elements or by a comparator provided at queue construction. By default, it uses the natural ordering, which means lower values have higher priority.