Tontti

#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<algorithm>
#include<cmath>
#include<utility>

using namespace std;

int64_t calc(const vector<vector<int64_t>> &foo, int64_t i, int64_t j, int64_t sqsize) {
  return foo[i][j] - ((i-sqsize >= 0)?foo[i-sqsize][j]:0) - ((j-sqsize >= 0)?foo[i][j-sqsize]:0) + ((i-sqsize >= 0 && j-sqsize >= 0)?foo[i-sqsize][j-sqsize]:0);
}

int main(void) {
  int64_t n,m,x;
  cin >> n >> m >> x;
  vector<vector<char>> woods(n,vector<char>(m));
  for(int64_t i=0;i<n;i++) {
    for(int64_t j=0;j<m;j++) {
      cin >> woods[i][j];
    }
  }
  vector<vector<int64_t>> foo(n,vector<int64_t>(m,0));
  for(int64_t i=0;i<n;i++) {
    for(int64_t j=0;j<m;j++) {
      if(woods[i][j] == '*') {
        foo[i][j]=((j-1>=0)?foo[i][j-1]:0)+((i-1>=0)?foo[i-1][j]:0)-((i-1>=0&&j-1>=0)?foo[i-1][j-1]:0)+1;
      } else {
        foo[i][j]=((j-1>=0)?foo[i][j-1]:0)+((i-1>=0)?foo[i-1][j]:0)-((i-1>=0&&j-1>=0)?foo[i-1][j-1]:0);
      }
    }
  }
  int64_t ways=0;
  for(int64_t i=0;i<n;i++) {
    for(int64_t j=0;j<m;j++) {
      int64_t sqsize=1;
      for(int64_t blah=2048;blah>=1;blah/=2) {
        while(sqsize+blah<=min(i+1,j+1) && calc(foo,i,j,sqsize+blah)<=x) sqsize+=blah;
      }
      if(calc(foo,i,j,sqsize) != x) continue;
      int64_t maxsize=sqsize;
      for(int64_t blah=2048;blah>=1;blah/=2) {
        while(sqsize-blah>0 && calc(foo,i,j,sqsize-blah)>=x) sqsize-=blah;
      }
      int64_t minsize=sqsize;
      ways+=maxsize-minsize+1;
    }
  }

  cout << ways << '\n';

  return 0;
}

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