清晰明了

import java.util.*;

public class Finder {
 public int findKth(int[] a, int n, int k) {
        // write code here
       quicksort(a,0,n-1,n-k);
        return a[n-k];
    }

    private void  quicksort(int[] a, int l,int r, int k) {
        if (l>=r)
            return ;
        int left=l-1;
        int right=r+1;
        int mid=a[(left+right)>>1];
        while (left<right){
            do {
                 left++;
            }
            while (a[left]<mid);
            do {
                right--;
            }
            while (a[right]>mid);
            if (left<right){
                int t=a[left];
                a[left]=a[right];
                a[right]=t;
            }
        }
        if (right>=k)quicksort(a,l,right,k);
        else  quicksort(a,right+1,r,k);
    }
}