Forest density

input/code.cpp: In function 'int main()':
input/code.cpp:21:19: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   21 |     for(int i=0; i<n; i++){
      |                  ~^~
input/code.cpp:25:23: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   25 |         for(int k=0; k<n; k++){
      |                      ~^~
input/code.cpp:33:19: warning: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Wsign-compare]
   33 |     for(int i=0; i<q; i++){
      |                  ~^~

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

typedef unsigned long long ull;

inline ull andmask(unsigned n){
    return ~((~0ULL) << n);
}

ull sums[1001][1001];

int main(){
    unsigned n, q;
    cin >> n >> q;

    vector<string> strs;
    strs.reserve(n);
    vector<ull> ls;
    ls.reserve(n);

    for(int i=0; i<n; i++){
        string s;
        cin >> s;

        for(int k=0; k<n; k++){
            sums[i][k] = (s[k] == '*')
                + (i > 0 ? sums[i-1][k] : 0)
                + (k > 0 ? sums[i][k-1] : 0)
                - (i > 0 && k > 0 ? sums[i-1][k-1] : 0);
        }
    }

    for(int i=0; i<q; i++){
        ull y1, x1, y2, x2;
        cin >> y1 >> x1 >> y2 >> x2;

        ull sum = sums[y2-1][x2-1]
            - (x1-1 ? sums[y2-1][x1-2] : 0)
            - (y1-1 ? sums[y1-2][x2-1] : 0)
            + (x1-1 && y1-1 ? sums[y1-2][x1-2] : 0);
        cout << sum << endl;
    }

    // vector<ull> rls;
    // rls.reserve(n);
    // for(int i=0; i<n; i++){
    //     ull ss = 0;
    //     for(int j=0; j<n; j++){
    //         ss = (ss << 1) & (strs[j][i] == '*');
    //     }
    //     rls.push_back(ss);
    // }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED