func_code_string: #include <iostream>   #include <bits/stdc++.h>      int i = 0, j = 0, g = 0;      #define int long long   #define float double      using namespace std;      void solve(void)   {       int n;          cin >> n;          int a[2*n], config = 0;          set <int> s;          for (i = 0; i < 2*n; i++)       {           cin >> a[i];              if (a[i] % 2 == 1)           {               config = -1;           }              s.insert(a[i]);       }          sort(a, a + 2*n);          if (config == -1 || s.size() != n)       {           cout <<  NO n ;           return;       }          j = 2;          int asum = 0, csum = 0;              for (i = 1; i <= n - 1; i++)       {           if ((a[2*i] - a[2*(i - 1)]) % j != 0)           {               cout <<  NO n ;               return;           }              asum += (a[2*i] - a[2*(i - 1)])/j;           csum += asum;              j += 2;       }          if (((a[0]/2) - csum <= 0) || ((((a[0]/2) - csum) % n) != 0))       {           cout <<  NO n ;           return;       }          cout <<  YES n ;   }      int32_t main(void)   {       ios_base::sync_with_stdio(false);       cin.tie(0);       cout.tie(0);          int t;          cin >> t;             while (t--)       {           solve();       }   }