题解 | #寻找第K大(快速排序 java)#

import java.util.*;

public class Solution {
    public int findKth(int[] a, int n, int K) {
        // write code here
        quickSort (a, 0, a.length - 1);

        return a[a.length - K];
    }

    private void quickSort(int[] arr, int left, int right) {
        if (left < right) {
            int bound = quick (arr, left, right);
            quickSort(arr, left, bound - 1);
            quickSort(arr, bound + 1, right);
        }
    }

    private int quick(int[] arr, int left, int right) {

        int temp = arr[left]; // 以最左边的数作为基准

        while (left < right) {
            while (left < right && arr[right] >= temp) {
                right--;
            }
            arr[left] = arr[right];
            while (left < right && arr[left] <= temp) {
                left++;
            }
            arr[right] = arr[left];
        }

        arr[left] = temp;

        return left;
    }
}