题解

#include <bits/stdc++.h>
using namespace std;

int f(int n, int k, vector<int>& numbers) {
    set<int> un(numbers.begin(), numbers.end());  
    vector<int> sun(un.begin(), un.end());  

    if (k > sun.size()) {
        return -1; 
    }

    sort(sun.begin(), sun.end());

    return sun[k - 1];
}

int main() {
    int n, k;
    cin >> n >> k;

    vector<int> numbers(n);
    for (int i = 0; i < n; ++i) {
        cin >> numbers[i];
    }

    int result = f(n, k, numbers);
    if (result == -1) {
        cout << "NO RESULT" << endl;
    } else {
        cout << result << endl;
    }

    return 0;
}