Codeforces Round #730 (Div. 2) B - Customising the Track Solution

Codeforces Round #730 (Div. 2) B - Customising the Track Solution 

Solution in C++: 

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

#include <bits/stdc++.h>

using namespace std;

int main()

{

    ios::sync_with_stdio(false);

    cin.tie(0);

    long long  t;

    cin>>t;

    while(t--)

    {

        long long  n,i,mod,ans,sum,a;

        sum=0;

        cin>>n;

        for(i=1; i<=n; i++)

        {

            cin>>a;

            sum+=a;

        }

        mod=sum%n;

        ans=(n-mod)*mod;

        cout<<ans<<"\n";

    }

    return 0;

}