Tontti

#include <iostream>
#include <string>
using namespace std;

int t[2000][2000];

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  
  long n, m, x;
  cin >> n >> m >> x;
  for (long i = 0; i < n; ++i) {
    string r;
    cin >> r;
    int sum = 0;
    for (long j = 0; j < m; ++j) {
      sum += r[j] == '*';
      if (i > 0) {
        sum += t[i-1][j];
        if (j > 0) sum -= t[i-1][j-1];
      }
      t[i][j] = sum;
    }
  }
  long r = 0;
  for (long i = 0; i < n; ++i) {
    for (long j = 0; j < m; ++j) {
      for (long s = 0; s < min(n-i, m-j); ++s) {
        long v = t[i+s][j+s];
        if (i > 0) v -= t[i-1][j+s];
        if (j > 0) v -= t[i+s][j-1];
        if (i > 0 && j > 0) v += t[i-1][j-1];
        if (v == x) r++;
        else if (v > x) break;
      }
    }
  }
  cout << r;
}

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: TIME LIMIT EXCEEDED

Test 12

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 3

Verdict: TIME LIMIT EXCEEDED