func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, m, a, b, x, cnt, ans;   deque<long long> V;   map<long long, long long> mp;   long long arr[1000001];   int main() {     cin >> n >> a >> b;     for (int i = 1; i <= n; i++) {       cin >> arr[i];     }     sort(arr + 1, arr + n + 1);     ans = (n - a) + 1;     x = arr[ans] - arr[b];     cout << x << endl;   }   