func_code_string: #include <bits/stdc++.h>   using namespace std;   #pragma GCC target( avx2 )   #pragma GCC optimization( unroll-loops )   #pragma GCC optimize( O2 )   constexpr int dx[] = {-1, 0, 1, 0, 1, 1, -1, -1};   constexpr int dy[] = {0, -1, 0, 1, 1, -1, 1, -1};   constexpr long long INF = 1999999999999999997;   constexpr int inf = INT_MAX;   constexpr int MAXSIZE = int(1e6) + 5;   constexpr auto PI = 3.14159265358979323846L;   constexpr auto oo = numeric_limits<int>::max() / 2 - 2;   constexpr auto eps = 1e-6;   constexpr auto mod = 1000000007;   constexpr auto MOD = 1000000007;   constexpr auto MOD9 = 1000000009;   constexpr auto maxn = 100006;   void fastio() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);   }   int n, m, k;   int fre;   char a[502][502];   int x = -1, y = -1;   bool visited[502][502];   int l;   void dfs(int x, int y) {     if (l == 0) return;     if (x + 1 < n && a[x + 1][y] ==  .  && !visited[x + 1][y] && l > 0) {       visited[x + 1][y] = 1;       l--;       dfs(x + 1, y);     }     if (l == 0) return;     if (y + 1 < m && a[x][y + 1] ==  .  && !visited[x][y + 1] && l > 0) {       visited[x][y + 1] = 1;       l--;       dfs(x, y + 1);     }     if (l == 0) return;     if (x - 1 >= 0 && a[x - 1][y] ==  .  && !visited[x - 1][y] && l > 0) {       visited[x - 1][y] = 1;       l--;       dfs(x - 1, y);     }     if (l == 0) return;     if (y - 1 < n && a[x][y - 1] ==  .  && !visited[x][y - 1] && l > 0) {       visited[x][y - 1] = 1;       l--;       dfs(x, y - 1);     }     if (l == 0) return;   }   int main() {     fastio();     cin >> n >> m >> k;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         cin >> a[i][j];         if (a[i][j] ==  . ) {           fre++;           if (x == -1) {             x = i, y = j;           }         }       }     }     l = fre - k;     int c = k;     dfs(x, y);     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         if (a[i][j] ==  .  && !visited[i][j] && c > 0) {           a[i][j] =  X ;           c--;         }         cout << a[i][j];       }       cout <<   n ;     }   }   