func_code_string: #include <bits/stdc++.h>   using namespace std;   bool isprime(long long int n) {     if (n < 2) return false;     for (long long int i = 2; i <= sqrt(n); i++)       if (n % i == 0) return false;     return true;   }   long long gcd(long long int a, long long int b) {     if (a == 0 || b == 0)       return a + b;     else       return gcd(b, a % b);   }   const int mx = 100000;   long long int b[mx], w[mx], dp[10][mx];   char c[1100][1100];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     long long int n, m, x, y;     cin >> n >> m >> x >> y;     for (long long int i = 1; i <= n; i++)       for (long long int j = 1; j <= m; j++) cin >> c[i][j];     for (long long int i = 1; i <= m; i++) {       long long int wt = 0, bl = 0;       for (long long int j = 1; j <= n; j++) {         if (c[j][i] ==  . )           wt++;         else           bl++;       }       w[i] = w[i - 1] + wt;       b[i] = b[i - 1] + bl;     }     for (long long int i = 1; i <= m; i++) {       dp[1][i] = 100000000;       dp[0][i] = 100000000;       for (long long int a = x; a <= y; a++) {         if (i - a >= 0) {           dp[1][i] = min(dp[0][i - a] + w[i] - w[i - a], dp[1][i]);           dp[0][i] = min(dp[1][i - a] + b[i] - b[i - a], dp[0][i]);         }       }     }     cout << min(dp[0][m], dp[1][m]);     return 0;   }   