Ruudukko

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

int t[1000][1000];
const int mod = 1000000007;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    ll sum = 0;
    cin >> n;
    for (int i = 0; i < n; ++i) for (int j = 0; j < n; ++j) {
        int r;
        cin >> r;
        ll vyk = (i+1) * (j+1);
        ll oak = (n - i) * (n - j);
        sum = (sum + vyk * oak * r) % mod;
    }
    cout << sum << endl;

    return 0;
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 2, 3

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED