有人用java写吗？最后两个超时了

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Main{
static int a[];
static void quickSort(int left,int right){
int l=left;
int r=right;
int mid=a[(l+r)/2];
int temp=0;
while(l<r){
    while(a[l]<mid)
        l++;
    while (a[r]>mid)
        r--;
    if(l>=r)
        break;
    temp=a[r];
    a[r]=a[l];
    a[l]=temp;
    if(mid==a[r])
        l++;
    if(mid==a[l])
        r--;
}
if(l==r){
    l++;
    r--;
}
if(l<right)
    quickSort(l,right);
if(r>left)
    quickSort(left,r);
}
public static void main(String[] args) throws Exception{
BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
String[] one=reader.readLine().split(" ");
int n=Integer.parseInt(one[0]);
int ai=Integer.parseInt(one[1]);
String[] q=reader.readLine().split(" ");
reader.close();
a=new int[q.length];
for(int i=0;i<n;i++){
    a[i]=Integer.parseInt(q[i]);
}
quickSort(0,n-1);
System.out.print(a[ai]);
}
}