answer.code: In function ‘void solve()’:
answer.code:87:9: error: ‘vis’ was not declared in this scope
   87 |         vis[i]=0;
      |         ^~~
answer.code:151:22: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’
  151 |             for(auto [u,v]:mp)
      |                      ^
answer.code: In member function ‘bool node::operator<(const node&)’:
answer.code:35:5: warning: control reaches end of non-void function [-Wreturn-type]
   35 |     }
      |     ^