60分求助！！！

#include <iostream>
#include <algorithm>

using namespace std;

int a[5000005];

int main(){
    int n,k;
    cin >> n >> k;
    for (int i = 1;i <= n;i++) cin >> a[i];
    sort(a + 1,a + n + 1);
    cout << a[++k];
    return 0;
}

后两个测试点TLE