func_code_string: #include <bits/stdc++.h>   using namespace std;   string n;   int sz;   long long mul;   long long ans;   long long powe(long long a, long long b) {     if (!b) return 1;     long long tmp = powe(a, b / 2);     tmp = (tmp * tmp) % 1000000007;     if (b % 2 == 1)       return (tmp * a) % 1000000007;     else       return tmp;   }   int main() {     cin >> n;     sz = ((int)n.size());     mul = powe(2, sz - 1);     long long tp = 1;     for (int i = sz - 1; i >= 0; i--) {       if (n[i] ==  1 ) {         ans = (ans + ((tp * mul) % 1000000007)) % 1000000007;       }       tp = (tp * 2) % 1000000007;     }     cout << ans << endl;     return 0;   }   