LeetCode70|最小K个数

示例：

输入：arr = [1,3,5,7,2,4,6,8], k = 4
输出：[1,2,3,4]
提示：

0 <= len(arr) <= 100000
0 <= k <= min(100000, len(arr))

 

 
import java.util.Arrays;
import java.util.PriorityQueue;

public class SmallestKTest2 {
    public static void main(String[] args) {
        int[] arr = {1, 3, 5, 7, 2, 4, 6, 8};
        int k = 4;
        int[] smallestK = smallestK2(arr, k);
        for (int j : smallestK) {
            System.out.print(j + "\t");
        }
    }

    public static int[] smallestK(int[] arr, int k) {
        Arrays.sort(arr);
        int[] array = new int[k];
        if (k >= 0) {
            System.arraycopy(arr, 0, array, 0, k);
        }
        return array;
    }

    public static int[] smallestK2(int[] arr, int k) {
        PriorityQueue<Integer> priorityQueue = new PriorityQueue<>(k, Integer::compareTo);
        for (int j : arr) {
            priorityQueue.offer(j);
        }
        int[] array = new int[k];
        for (int i = 0; i < k; i++) {
            array[i] = priorityQueue.poll();
        }
        return array;
    }
}