func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int N;     cin >> N;     int a[10000], b[10000];     for (int n = 0; n < N; n++) {       cout <<  ?   << 0 <<     << n << endl;       cin >> a[n];     }     for (int n = 0; n < N; n++) {       cout <<  ?   << n <<     << 0 << endl;       cin >> b[n];     }     int nm = 0, fa = 0;     int ac[10000], bc[10000];     for (int n = 0; n < N; n++) {       for (int x = 0; x < N; x++) {         ac[x] = a[x] ^ n;       }       for (int x = 0; x < N; x++) {         bc[x] = b[x] ^ ac[0];       }       bool p = true;       for (int x = 0; x < N; x++) {         if (ac[bc[x]] != x) {           p = false;         }       }       if (p) {         fa = n;         nm++;       }     }     cout <<  !  << endl;     cout << nm << endl;     fa = fa ^ a[0];     for (int x = 0; x < N; x++) {       if (x) cout <<    ;       cout << (fa ^ b[x]);     }     cout << endl;     return 0;   }   