func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> v1, v2, v3;   int n, flag;   int main() {     cin >> n;     int t = 0;     string s1, s2;     cin >> s1 >> s2;     for (int i = 0; i < n; i++) {       if (s1[i] ==  1  && s2[i] ==  0 ) v1.push_back(i + 1);       if (s1[i] ==  0  && s2[i] ==  1 ) v1.push_back(i + 1);       if (s1[i] ==  1  && s2[i] ==  1 ) v2.push_back(i + 1);       if (s1[i] ==  0  && s2[i] ==  0 ) v3.push_back(i + 1);       if (s2[i] ==  1 ) t++;     }     int a = v1.size(), b = v2.size(), c = v3.size();     for (int i = 0; i <= b; i++) {       int x = t - 2 * i;       if (x >= 0 && n / 2 - i - x >= 0 && x <= a && n / 2 - i - x <= c) {         a = x;         b = i;         c = n / 2 - i - x;         flag = 1;       }     }     if (flag) {       for (int i = 0; i < a; i++) cout << v1[i] <<    ;       for (int i = 0; i < b; i++) cout << v2[i] <<    ;       for (int i = 0; i < c; i++) cout << v3[i] <<    ;     } else       cout <<  -1 ;     return 0;   }   