我的池沼写法

const ll N = 1e9;
ll d1[4] = {0, 3, 6, 7};
ll d2[4] = {0, 2, 3, 3};
ll S(ll x, ll y) {
	x += N, y += N;
	ll res = 4 * (x / 4) * y;
	res += (y / 2) * d1[x % 4];
	if(y % 2) res += d2[x % 4];
	return res;
}
void solve() {
	ll A, B, C, D;
	cin >> A >> B >> C >> D;
	cout << S(C, D) - S(C, B) - S(A, D) + S(A, B) << endl;
}