stations.cpp: In function 'int dfs(int, int, int, bool)':
stations.cpp:11:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
11 | for (int i=0; i<adj[U].size(); i++)
| ~^~~~~~~~~~~~~~
stations.cpp:20:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
20 | for (int i=0; i<adj[U].size(); i++)
| ~^~~~~~~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:50:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
50 | for (int i=0; i<C.size(); i++)
| ~^~~~~~~~~
stations.cpp:63:1: warning: control reaches end of non-void function [-Wreturn-type]
63 | }
| ^