answer.code: In function ‘std::vector<int> longest_trip(int, int)’:
answer.code:81:28: error: expected initializer before ‘.’ token
   81 |             int l = 0, v[0].size() - 1;
      |                            ^
answer.code:82:25: error: ‘r’ was not declared in this scope
   82 |             while (l <= r) {
      |                         ^
answer.code:102:20: error: ‘r’ was not declared in this scope
  102 |             l = 0, r = v[1].size();
      |                    ^
answer.code:109:50: error: expected ‘)’ before ‘{’ token
  109 |                 if (are_connected({v[0][i]}, cur) {
      |                    ~                             ^~
      |                                                  )
answer.code:114:13: error: expected primary-expression before ‘}’ token
  114 |             }
      |             ^