func_code_string: #include <bits/stdc++.h>   using namespace std;   long long int pp(long long int a, long long int b) {     if (b == 0) return 1;     long long int t = pp(a, b / 2);     if (b % 2 == 0)       return t * t;     else       return t * t * a;   }   string ss(string s, long long int j) {     for (long long int i = 0; i < j; i++) {       if (s[i] ==  0 )         s[i] =  1 ;       else         s[i] =  0 ;     }     long long int l = 0, r = j - 1;     while (l < r) {       swap(s[l], s[r]);       l++;       r--;     }     return s;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     ;     long long int q;     cin >> q;     while (q--) {       long long int i, j, k, n, m, x, y, l, r, c = 0;       string s, s1, s2 =   ;       cin >> n;       cin >> s >> s1;       vector<long long int> v;       for (i = n - 1; i > 0; i--) {         if (s[i] == s1[i])           continue;         else {           if ((s1[i] ==  0  && s[i] ==  1  && s[0] ==  1 ) ||               (s1[i] ==  1  && s[i] ==  0  && s[0] ==  0 )) {             v.push_back(i + 1);             s = ss(s, i + 1);           } else if (s1[i] ==  0  && s[i] ==  1  && s[0] ==  0 ) {             v.push_back(1);             s[0] =  1 ;             v.push_back(i + 1);             s = ss(s, i + 1);           } else {             v.push_back(1);             s[0] =  0 ;             v.push_back(i + 1);             s = ss(s, i + 1);           }         }       }       if (s[0] != s1[0]) v.push_back(1);       cout << v.size() <<    ;       for (i = 0; i < v.size(); i++) cout << v[i] <<    ;       cout << endl;     }   }   