Java中优先级队列的轮询方法详解与应用

Priority_Queue.poll()


// Java code to illustrate poll()
import java.util.*;
public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<String> queue = new PriorityQueue<String>();
        // Use add() method to add elements into the Queue
        queue.add("Welcome");
        queue.add("To");
        queue.add("Geeks");
        queue.add("For");
        queue.add("Geeks");
        // Displaying the PriorityQueue
        System.out.println("Initial PriorityQueue: " + queue);
        // Fetching and removing the element at the head of the queue
        System.out.println("The element at the head of the"
                           + " queue is: " + queue.poll());
        // Displaying the Queue after the Operation
        System.out.println("Final PriorityQueue: " + queue);
    }
}


Initial PriorityQueue: [For, Geeks, To, Welcome, Geeks]
The element at the head of the queue is: For
Final PriorityQueue: [Geeks, Geeks, To, Welcome]


// Java code to illustrate poll()
import java.util.*;
public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<Integer> queue = new PriorityQueue<Integer>();
        // Use add() method to add elements into the Queue
        queue.add(10);
        queue.add(15);
        queue.add(30);
        queue.add(20);
        queue.add(5);
        // Displaying the PriorityQueue
        System.out.println("Initial PriorityQueue: " + queue);
        // Fetching the element at the head of the queue
        System.out.println("The element at the head of the"
                           + " queue is: " + queue.poll());
        // Displaying the Queue after the Operation
        System.out.println("Final PriorityQueue: " + queue);
    }
}


Initial PriorityQueue: [5, 10, 30, 20, 15]
The element at the head of the queue is: 5
Final PriorityQueue: [10, 15, 30, 20]