在优先级相等的情况下保持PriorityQueue插入顺序

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

class Element {
    private int value;
    private int insertOrder;

    public Element(int value, int insertOrder) {
        this.value = value;
        this.insertOrder = insertOrder;
    }

    public int getValue() {
        return value;
    }

    public int getInsertOrder() {
        return insertOrder;
    }
}

class ElementComparator implements Comparator<Element> {
    @Override
    public int compare(Element e1, Element e2) {
        if (e1.getValue() < e2.getValue()) {
            return -1;
        } else if (e1.getValue() > e2.getValue()) {
            return 1;
        } else {
            return Integer.compare(e1.getInsertOrder(), e2.getInsertOrder());
        }
    }
}

public class Main {
    public static void main(String[] args) {
        PriorityQueue<Element> pq = new PriorityQueue<>(new ElementComparator());

        // 插入元素
        pq.offer(new Element(5, 1));
        pq.offer(new Element(3, 2));
        pq.offer(new Element(5, 3));
        pq.offer(new Element(2, 4));
        pq.offer(new Element(3, 5));

        // 输出队列中的元素
        while (!pq.isEmpty()) {
            Element element = pq.poll();
            System.out.println("Value: " + element.getValue() + ", Insert Order: " + element.getInsertOrder());
        }
    }
}