func_code_string: #include <bits/stdc++.h>   using namespace std;   char s[1000010];   int main() {     int k;     cin >> k;     scanf( %s , s);     int n = strlen(s);     int a[n + 1];     a[0] = 0;     for (int i = 1; i < n + 1; i++) {       a[i] = a[i - 1] + ((s[i - 1] ==  1 ) ? 1 : 0);     }     long long int ans = 0;     for (int i = 1; i < n + 1; i++) {       int ss = a[i - 1] + k;       if (a[n] < ss) continue;       int g = lower_bound(a + i, a + n + 1, ss) - a;       int h = upper_bound(a + i, a + n + 1, ss) - a;       ans += (h - g);     }     cout << ans;     return 0;   }   