60求助

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,k,a[5000005]={};
    cin >> n >> k;
    for(int i=0;i<n;i++) cin >> a[i];
    nth_element(a,a+k,a+n);
    cout << a[k];
    return 0;
}

https://www.luogu.com.cn/record/75679061