func_code_string: #include <bits/stdc++.h>   using namespace std;   int INF = 100000000;   int n, m, x, y;   char ch;   long long int pre[2][(int)1e3 + 5], dp[2][(int)1e3 + 5];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cin >> n >> m >> x >> y;     memset(pre, 0, sizeof(pre));     memset(dp, 0, sizeof(dp));     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         cin >> ch;         if (ch ==  . )           pre[1][j]++;         else           pre[0][j]++;       }     }     for (int i = 1; i <= m; i++) {       pre[0][i] += pre[0][i - 1];       pre[1][i] += pre[1][i - 1];     }     for (int i = 1; i <= m; i++) {       dp[0][i] = INT_MAX;       dp[1][i] = INT_MAX;       for (int j = x; j <= y; j++) {         if (i - j < 0) {           break;         }         dp[0][i] = min(dp[0][i], dp[1][i - j] + pre[0][i] - pre[0][i - j]);         dp[1][i] = min(dp[1][i], dp[0][i - j] + pre[1][i] - pre[1][i - j]);       }     }     cout << min(dp[0][m], dp[1][m]) << endl;     return 0;   }   