剑指Offer（二十九）-- 最小的k个数

import java.util.ArrayList;
import java.util.PriorityQueue;

public class Solution {
    public ArrayList<Integer> GetLeastNumbers_Solution(int[] input, int k) {
        if (input == null || k > input.length || k <= 0) {
            return new ArrayList<>();
        }
        PriorityQueue<Integer> priorityQueue = new PriorityQueue<>((o1, o2) -> o2 - o1);
        for (int num : input) {
            priorityQueue.add(num);
            if (priorityQueue.size() > k) {
                priorityQueue.poll();
            }
        }
        return new ArrayList<>(priorityQueue);
    }
}