LeetCode--面试题40. 最小的k个数

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方法1：排序之后取前 k 个

class Solution {
    public int[] getLeastNumbers(int[] arr, int k) {
        if(k == 0 || arr.length == 0) return new int[0];
		Arrays.sort(arr);
		int[] res = new int[k];
		for(int i = 0;i < k;i++) res[i] = arr[i];
		return res;
    }
}

方法2：堆排序

import java.util.PriorityQueue;

class Solution {
	
	public int[] getLeastNumbers(int[] arr, int k) {
		if(k == 0 || arr.length == 0) return new int[0];
		PriorityQueue<Integer> q = new PriorityQueue<Integer>(k);
		for(int i = 0;i < arr.length;i++) {
			q.add(arr[i]);
		}
		int[] res = new int[k];
		for(int i = 0;i < k;i++) res[i] = q.poll();
		return res;
    }
}