Tontti

#include <iostream>
using namespace std;
const int MN = 2222;
int t[MN][MN];
int getSum(int x1, int y1, int x2, int y2) {
    return t[x2+1][y2+1] - t[x2+1][y1] - t[x1][y2+1] + t[x1][y1];
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n,m,k;
    cin>>n>>m>>k;
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < m; ++j) {
            char q;
            cin>>q;
            if(q == '*') {
                t[i+1][j+1] = 1;
            }
                t[i+1][j+1] += t[i][j+1] + t[i+1][j] - t[i][j];
        }
    }
    long long ans = 0;
    for(int i = 0; i < n; ++i) {
        for(int j = 0; j < m; ++j) {
            int lo = 0; 
            int hi = min(n-i-1, m-j-1);
            int frst = 0;
            while(lo <= hi) {
                int mid = (lo+hi)/2;
                if(getSum(i, j, i+mid, j+mid) >= k) {
                    frst = mid;
                    hi = mid-1;
                }
                else {
                    lo = mid+1;
                }
            }
            if(getSum(i, j, i+frst, j+frst) != k) continue;
            lo = 0; 
            hi = min(n-i-1, m-j-1);
            int last = 0;
            while(lo <= hi) {
                int mid = (lo+hi)/2;
                if(getSum(i, j, i+mid, j+mid) <= k) {
                    last = mid;
                    lo = mid+1;
                }
                else {
                    hi = mid-1;
                }
            }
            if(getSum(i, j, i+last, j+last) != k) continue;
            ans += last-frst+1;
        }
    }
    cout<<ans<<'\n';
}

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: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED