func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   string a, b;   void perform(int len) {     for (int i = 0; i < len / 2; ++i) {       if (a[i] == a[len - 1 - i]) {         a[i] =  0  +  1  - a[i];         a[len - 1 - i] =  0  +  1  - a[len - 1 - i];       }     }     if (len & 1) a[len / 2] =  0  +  1  - a[len / 2];   }   int main() {     int t;     cin >> t;     while (t--) {       cin >> n >> a >> b;       int k = 0;       vector<int> ops;       for (int i = n - 1; i >= 0; --i) {         if (a[i] != a[0]) perform(1), ++k, ops.push_back(1);         if (a[i] != b[i]) perform(i + 1), ++k, ops.push_back(i + 1);       }       cout << k <<    ;       for (int x : ops) cout << x <<    ;       cout << endl;     }     return 0;   }   