Kertotaulu

#include <iostream>
using namespace std;

typedef long long ll;
#define MOD 1000000007LL

inline ll mod(ll num) {
    if (num < 0LL) num += MOD;
    return num%MOD;
}

ll calc(ll row, ll col) {
    ll mm1  = mod(col * (col+1LL)) / 2LL;
    ll rr1 = mod(row * (row+1LL)) / 2LL;
    return mod(mm1 * rr1);
}

int main() {
    ll row1,col1,row2,col2;
    cin >> row1 >> col1 >> row2 >> col2;
    ll total = calc(row2,col2);
    ll top = calc(row1-1LL, col2);
    ll left = calc(row2, col1-1LL);
    ll tl = calc(row1-1LL, col1-1LL);
    cout << mod (total - top - left + tl) << endl;
    return 0;
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: WRONG ANSWER

Test 7

Group: 2

Verdict: WRONG ANSWER

Test 8

Group: 2

Verdict: WRONG ANSWER

Test 9

Group: 2

Verdict: WRONG ANSWER

Test 10

Group: 2

Verdict: WRONG ANSWER

Test 11

Group: 3

Verdict: WRONG ANSWER

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: WRONG ANSWER

Test 15

Group: 3

Verdict: ACCEPTED