answer.code: In function ‘int main()’:
answer.code:13:16: error: missing template arguments before ‘vis’
   13 |         vector vis(n, vector<bool>(256));
      |                ^~~
answer.code: In lambda function:
answer.code:36:17: error: ‘vis’ was not declared in this scope
   36 |             if (vis[i][v]) {
      |                 ^~~
answer.code:39:13: error: ‘vis’ was not declared in this scope
   39 |             vis[i][v] = true;
      |             ^~~
answer.code:40:18: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’
   40 |             auto [t, vl, to] = que[i];
      |                  ^
answer.code:52:9: warning: control reaches end of non-void function [-Wreturn-type]
   52 |         };
      |         ^