func_code_string: #include <bits/stdc++.h>   using namespace std;   char c[100005];   int cut[100005], num[100005];   int f[100005], h[2][100005];   int main() {     int n, m;     cin >> n >> c + 1 >> m;     for (int i = 1; i <= n; i++) {       num[i] = num[i - 1];       if (c[i] ==  a )         h[0][i] = h[1][i - 1] + 1;       else if (c[i] ==  b )         h[1][i] = h[0][i - 1] + 1;       else {         h[0][i] = h[1][i - 1] + 1;         h[1][i] = h[0][i - 1] + 1;         num[i]++;       }       f[i] = f[i - 1], cut[i] = cut[i - 1];       if (h[(m + 1) & 1][i] >= m) {         if (f[i] < f[i - m] + 1) {           f[i] = f[i - m] + 1, cut[i] = cut[i - m] + num[i] - num[i - m];         }         if (f[i] == f[i - m] + 1) {           cut[i] = min(cut[i], cut[i - m] + num[i] - num[i - m]);         }       }     }     cout << cut[n] << endl;   }   