func_code_string: #include <bits/stdc++.h>   using namespace std;   void solve() {     int a, b, n;     cin >> n >> a >> b;     vector<int> A(n);     for (int &x : A) cin >> x;     sort(A.begin(), A.end());     if (A[b] - A[b - 1] == 0) {       cout <<  0 n ;       return;     }     cout << A[b] - A[b - 1] <<   n ;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     solve();   }   