https://blog.csdn.net/u011386173/article/details/124730572

自定义大根堆的比较器

import java.util.Comparator;
import java.util.PriorityQueue;

public class PriorityQueueComparator {
	
	
	public static class MaxHeapComparator implements Comparator<Integer> {

		@Override
		public int compare(Integer o1, Integer o2) {
			return o2 - o1;
		}
		
	}

	public static void main(String[] args) {
		//默认小根堆
		PriorityQueue<Integer> queue = new PriorityQueue<>();
		queue.add(0);
		queue.add(5);
		System.out.println(queue.peek()); //0
		
		queue.add(7);
		queue.add(-1);
		System.out.println(queue.peek()); //-1
		
		while (!queue.isEmpty()) {
			System.out.println(queue.poll());//-1 0 5 7
		}

		
		System.out.println("大根堆");
		PriorityQueue<Integer> maxHeap = new PriorityQueue<>(new MaxHeapComparator()); //传入自定义的比较器
		maxHeap.add(4);
		maxHeap.add(7);
		maxHeap.add(0);
		
		System.out.println(maxHeap.peek()); //7
		
		while (!maxHeap.isEmpty()) {
			System.out.println(maxHeap.poll()); //7 4 0
		}
		
	}

}