func_code_string: #include <bits/stdc++.h>   bool office[25][25];   size_t m, n;   bool check(size_t x1, size_t y1, size_t x2, size_t y2) {     for (size_t x = x1; x <= x2; ++x) {       for (size_t y = y1; y <= y2; ++y) {         if (office[x][y]) {           return false;         }       }     }     return true;   }   bool check(size_t x, size_t y) {     for (size_t i = 0; i < m - x; ++i) {       for (size_t j = 0; j < n - y; ++j) {         if (check(i, j, i + x, j + y)) {           return true;         }       }     }     return false;   }   int main() {     std::cin >> m >> n;     std::string row;     size_t i = 0;     while (std::cin >> row) {       for (size_t j = 0; j < row.size(); ++j) {         office[i][j] = row[j] ==  1 ;       }       ++i;     }     size_t best = 4;     for (size_t x = 0; x < m; ++x) {       for (size_t y = 0; y < n; ++y) {         size_t p = (x + y + 2) * 2;         if (p > best && check(x, y)) {           best = p;         }       }     }     std::cout << best;   }   