Kertotaulu

input/code.cpp: In function 'int main()':
input/code.cpp:36:5: warning: unused variable 'ed' [-Wunused-variable]
  ll ed = (y2*x2)-(y1*x1);
     ^

#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long

#define pii pair<int, int>
#define pll pair<long long, long long>

#define defmod 1000000007
using namespace std;

ll pot(ll x, int n) {
	if (n == 0) return 1;
	if (n%2 == 1) return (pot(x,n-1)*x)%defmod;
	ll t = pot(x,n/2);
	return (t*t)%defmod;
}

ll inv(ll x) {
	return pot(x, defmod-2);
}

ll asum(ll n, ll a1, ll d){
	return ((n*(a1%defmod+((n-1)*d)%defmod+a1))%defmod*inv(2LL))%defmod;
}
ll asumnomod(ll n, ll a1, ll d){
	return (n*(a1+(n-1)*d+a1))/2;
}
int main(){
	cin.sync_with_stdio(0);
	cin.tie(0);
	
	ll y1, x1, y2, x2;
	cin >> y1 >> x1 >> y2 >> x2;
	
	ll ed = (y2*x2)-(y1*x1);
	ll n = (x2-x1)+1;
	ll m = (y2-y1)+1;
	
	if(n == 1){
		cout << asum(m, y1*x1, x1) << endl;
		return 0;
	}
	if(m == 1){
		cout << asum(n, y1*x1, y1) << endl;
		return 0;
	}
	ll eka = asum(n, y1*x1, y1);
	ll toka = asum(n, (y1+1)*x1, y1+1);
	ll d = toka-eka;
	d = ((d%defmod)+defmod)%defmod;
	//cout << eka << " " << toka << endl;
	cout << (((asum(m, eka, d)%defmod)+defmod)%defmod) << 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: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: WRONG ANSWER

Test 12

Group: 3

Verdict: WRONG ANSWER

Test 13

Group: 3

Verdict: WRONG ANSWER

Test 14

Group: 3

Verdict: WRONG ANSWER

Test 15

Group: 3

Verdict: ACCEPTED