func_code_string: #include <bits/stdc++.h>   using namespace std;   long long op[1000010];   int main() {     op[1] = 1LL;     for (int i = 2; i <= 1000000; i++) {       op[i] = op[i - 1] * 2 + 1;       op[i] %= 1000000007;     }     string s;     cin >> s;     long long cnt = 0;     int a = 0;     int b = 0;     for (int i = 0; i < s.size(); i++) {       if (s[i] ==  a )         a++;       else {         cnt += op[a];         cnt %= 1000000007;       }     }     cout << cnt << endl;   }   