func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int a, b, c;     bool o00, o01, o10, o11;     a = b = c = 0;     string s;     cin >> s;     string::iterator its;     its = s.begin();     for (; its != s.end(); ++its) {       if (*its ==  1 )         ++a;       else if (*its ==  0 )         ++b;       else if (*its ==  ? )         ++c;     }     o00 = (a < b + c);     o11 = (a + c > b + 1);     --its;     o01 = o10 = false;     int x1, x2;     x1 = (b + c - a + (a + b + c) % 2) / 2;     x2 = c - x1;     if (x1 >= 0 && x1 <= c) {       if (*its ==  0  || (*its ==  ?  && x2)) o10 = true;       if (*its ==  1  || (*its ==  ?  && x1)) o01 = true;     }     if (o00) cout <<  00 n ;     if (o01) cout <<  01 n ;     if (o10) cout <<  10 n ;     if (o11) cout <<  11 n ;     return 0;   }   