stations.cpp: In function 'void dfs(int)':
stations.cpp:14:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
14 | for(int i=0;i<Q[x].size();i++)
| ~^~~~~~~~~~~~
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:33:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
33 | for(int i=0;i<u.size();i++)
| ~^~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:52:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
52 | for(int i=1;i<c.size();i++)
| ~^~~~~~~~~
stations.cpp:57:1: warning: control reaches end of non-void function [-Wreturn-type]
57 | }
| ^