stations.cpp: In function 'void dfs(int, int)':
stations.cpp:15:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
15 | for (int j = 0; j < vi[x].size(); j++){
| ~~^~~~~~~~~~~~~~
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:30:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
30 | for (int i = 0; i < u.size(); i++){
| ~~^~~~~~~~~~
stations.cpp:31:18: error: 'class std::vector<int>' has no member named 'pb'
31 | vi[u[i]].pb(v[i]);
| ^~
stations.cpp:32:18: error: 'class std::vector<int>' has no member named 'pb'
32 | vi[v[i]].pb(u[i]);
| ^~
stations.cpp:37:16: error: 'class std::vector<int>' has no member named 'pb'
37 | labels.pb((d[i].f) * 1000 + d[i].s);
| ^~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:43:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
43 | for (int i = 1; i < v1.size();i++)
| ~~^~~~~~~~~~~