util之PriorityQueue

定義： PriorityQueue<Integer> queue = new PriorityQueue<Integer>();

java中的優先隊列默認從小到大

//自定義
//從大到小

import java.util.PriorityQueue;
import java.util.Scanner;
class node implements Comparable<node>{

int x; @Override public int compareTo(node o) { // TODO Auto-generated method stub
        return o.x-this.x; } } public class Main { static PriorityQueue<Integer> queue = new PriorityQueue<Integer>(); static PriorityQueue<node> q = new PriorityQueue<node>(); public static void main(String[] args) { Scanner cin = new Scanner(System.in); queue.offer(5); queue.offer(10); queue.offer(15); queue.offer(3); queue.offer(1); queue.offer(6); while(!queue.isEmpty()) { System.out.println(queue.poll()); } for(int i=1;i<=5;i++) { node xNode = new node(); xNode.x = cin.nextInt(); q.offer(xNode); } while(!q.isEmpty()) { System.out.println(q.poll().x); } } }