func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     int test;     cin >> test;     while (test--) {       int n;       cin >> n;       string s;       cin >> s;       for (int i = 0; i < n; i++) {         if (s[i] !=  ? ) {           int j = i - 1;           while (j >= 0 && s[j] ==  ? ) {             if (s[j + 1] ==  R ) {               s[j] =  B ;             } else {               s[j] =  R ;             }             j--;           }         }       }       reverse((s).begin(), (s).end());       for (int i = 0; i < n; i++) {         if (s[i] !=  ? ) {           int j = i - 1;           while (j >= 0 && s[j] ==  ? ) {             if (s[j + 1] ==  R ) {               s[j] =  B ;             } else {               s[j] =  R ;             }             j--;           }         }       }       reverse((s).begin(), (s).end());       if (s[0] ==  ? ) {         for (int i = 0; i < n; i++) {           if (i % 2) {             s[i] =  R ;           } else {             s[i] =  B ;           }         }       }       cout << s <<   n ;     }   }   