Forest density

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int a[1001][1001];

int main() {
	int n, q;
	cin >> n >> q;
	for (int i=0; i<=n; i++) {
		a[0][i] = 0;
		a[i][0] = 0;
	}
	for (int i=1; i<=n; i++) {
		for (int j=1; j<=n; j++) {
			char b;
			cin >> b;
			int c;
			if (b == '*') c = 1;
			else c = 0;
			a[i][j] = c + a[i-1][j] + a[i][j-1] - a[i-1][j-1];
		}
	}

	for (int i=0; i<q; i++) {
		int y1,x1,y2,x2;
		cin >> y1 >> x1 >> y2 >> x2;
		int out;
		out = a[y2][x2] - a[y1-1][x2] - a[y2][x1-1] + a[y1-1][x1-1];
		cout << out << '\n';
	}

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED