answer.code: In function ‘void dfs(int, int, long long int*)’:
answer.code:11:39: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   11 | void dfs(int x,int fa,LL *d){for(auto [y,w]:E[x]) if(y!=fa) d[y]=d[x]+w,dfs(y,x,d);}
      |                                       ^
answer.code: In function ‘void dij(int)’:
answer.code:19:22: warning: structured bindings only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   19 |                 auto [x,D]=q.top();q.pop();
      |                      ^
/usr/bin/ld: /tmp/ccZfk9Dt.o: in function `main':
implementer.cpp:(.text.startup+0x35e): undefined reference to `travel(std::vector<long long, std::allocator<long long> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status