NC88 寻找第K大

import java.util.*;

public class Solution {
    private int K;
    public int findKth(int[] a, int n, int K) {
        // write code here
        this.K = K;
        quickSort(a,0,a.length-1);
        return a[K-1];
    }
    public void quickSort(int[] a,int l, int r){
        if(l>=r)
            return;
        int t = a[l];
        int i =l;
        int j = r;
        while(i<j){
            while(i<j&&t>=a[j]){
                j--;
            }
            while(i<j&&t<=a[i]){
                i++;
            }
            int temp = a[i];
            a[i] = a[j];
            a[j] = temp;
        }
        a[l] = a[i];
        a[i] = t;
        if(i==K-1)
            return;
        quickSort(a,l,i-1);
        quickSort(a,i+1,r);
    }
}