Ruudukko

#include <bits/stdc++.h>

#define ll long long
#define M 1000000007

using namespace std;

int main() {
    ll n;
    cin>>n;
    ll a[n][n];
    ll ans = 0;
    for (ll i = 0; i < n; i++) {
        for (ll j = 0; j < n; j++) {
            cin>>a[i][j];
            ll x = a[i][j] * (i + 1) * (n - i);
            x %= M;
            x *= (j + 1) * (n - j);
            x %= M;
            ans += x;
            ans %= M;
        }
    }
    cout<<ans<<endl;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED