本来以为有重复的数，可一提交发现没有

#include<iostream>
#include<cstdio>
#include<algorithm>
#define ll long long
using namespace std;
const int MAXN=1e6;
ll n,k,a[MAXN+5];
int main(){
    scanf("%lld%lld",&n,&k);
    for(int i=1;i<=n;i++) scanf("%lld",&a[i]);
    sort(a+1,a+n+1);
    cout<<a[n-k+1];
    return 0;
}

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
    long long n,k,a[1000005];
    cin >> n >> k;
    for(int i=1;i<=n;i++)
        cin >> a[i];
    sort(a+1,a+n+1);
    cout << a[n-k+1];
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
int cmd(int a,int b)
{
    return a>b;
}
int main()
{
    int n,k;
    cin>>n>>k;
    int a[n+1];
    for (int i=1;i<=n;i++)
        cin>>a[i];
    sort(a+1,a+n+1,cmd);
    cout<<a[k];
    return 0;
}//sort从大到小排序并输出第k项就可以了