func_code_string: #include <bits/stdc++.h>   using namespace std;   int AR[1000000 + 7];   int main() {     int cnt = 0, k;     string s;     cin >> k >> s;     AR[0] = 1;     int64_t r = 0;     for (int i = 0; s[i] !=   0 ; i++) {       if (s[i] ==  1 ) cnt++;       if (cnt >= k) r += AR[cnt - k];       AR[cnt]++;     }     printf( %I64d n , r);     return 0;   }   