介绍一下PriorityQueue的堆排序三种常见用法

public class PriorityQueueDemo {
    public static void main(String[] args) {
        // 创建小顶堆（默认）
        System.out.println("=== 小顶堆示例 ===");
        PriorityQueue<Integer> minHeap = new PriorityQueue<>();
        
        // 添加元素
        minHeap.offer(5);
        minHeap.offer(1);
        minHeap.offer(10);
        minHeap.offer(3);
        
        System.out.println("小顶堆出队顺序：");
        while (!minHeap.isEmpty()) {
            System.out.print(minHeap.poll() + " ");  // 输出：1 3 5 10
        }
        
        System.out.println("\n\n=== 大顶堆示例 ===");
        // 使用Comparator创建大顶堆
        PriorityQueue<Integer> maxHeap = new PriorityQueue<>((a, b) -> b - a);
        
        maxHeap.offer(5);
        maxHeap.offer(1);
        maxHeap.offer(10);
        maxHeap.offer(3);
        
        System.out.println("大顶堆出队顺序：");
        while (!maxHeap.isEmpty()) {
            System.out.print(maxHeap.poll() + " ");  // 输出：10 5 3 1
        }
        
        System.out.println("\n\n=== 字符串优先队列 ===");
        PriorityQueue<String> stringQueue = new PriorityQueue<>();
        
        stringQueue.offer("banana");
        stringQueue.offer("apple");
        stringQueue.offer("cherry");
        
        System.out.println("字符串小顶堆出队顺序：");
        while (!stringQueue.isEmpty()) {
            System.out.print(stringQueue.poll() + " ");  // 按字典序输出
        }
    }
}