func_code_string: #include <bits/stdc++.h>   using namespace std;   double EPS = 1e-9;   long long INF = 1000000000000000005ll;   double PI = acos(-1);   inline string IntToString(long long int a) {     char x[100];     sprintf(x,  %lld , a);     string s = x;     return s;   }   inline long long int StringToInt(string a) {     char x[100];     long long int res;     strcpy(x, a.c_str());     sscanf(x,  %lld , &res);     return res;   }   inline string uppercase(string s) {     int n = (int)s.size();     for (long long int i = 0; i < n; i++)       if (s[i] >=  a  && s[i] <=  z ) s[i] = s[i] -  a  +  A ;     return s;   }   inline string lowercase(string s) {     int n = (int)s.size();     for (long long int i = 0; i < n; i++)       if (s[i] >=  A  && s[i] <=  Z ) s[i] = s[i] -  A  +  a ;     return s;   }   bool sortcol(const vector<long long int>& v1, const vector<long long int>& v2) {     return v1[0] > v2[0];   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     long long int t;     cin >> t;     while (t-- > 0) {       long long int n;       cin >> n;       n *= 2;       long long int a[n];       for (long long int i = 0; i < n; i++) cin >> a[i];       sort(a, a + n);       cout << a[n / 2] - a[n / 2 - 1] <<   n ;     }     return 0;   }   