func_code_string: #include <bits/stdc++.h>   using namespace std;   void solve() {     long long n, m, k, i, j, count = 0, sum = 0, maxi = 0, mini = 1e18, flag = 0;     cin >> n;     vector<long long> res;     vector<char> temp;     string a, b;     cin >> a >> b;     if (a == b) {       cout << 0 <<   n ;       return;     }     if (n == 1 && a[0] != b[0]) {       cout << 1 <<     << 1 <<   n ;       return;     }     for (i = 0; i < n / 2; i++) {       temp.push_back(a[i]);       if (a[n - i - 1] ==  1 )         temp.push_back( 0 );       else         temp.push_back( 1 );     }     if (n % 2) temp.push_back(a[n / 2]);     i = 0;     j = n - 1;     while (j > 0) {       if (temp[i] == b[j]) {         res.push_back(0);         res.push_back(j);       } else         res.push_back(j);       j--;       i++;     }     if (j == 0) {       if (temp[i] == b[j])         ;       else         res.push_back(0);     }     cout << res.size() <<    ;     for (i = 0; i < res.size(); i++) {       cout << res[i] + 1 <<    ;     }     cout <<   n ;   }   int32_t main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     long long t = 1;     cin >> t;     while (t--) {       solve();     }   }   