stations.cpp: In function 'void dfs(int, int)':
stations.cpp:9:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
9 | for (int j=0;j<vec[x].size();j++){
| ~^~~~~~~~~~~~~~
stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:23:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
23 | for (int i=0;i<u.size();i++){
| ~^~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:36:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for (int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:42:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
42 | for (int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:47:1: warning: control reaches end of non-void function [-Wreturn-type]
47 | }
| ^