stations.cpp: In function 'void dfs(int, int)':
stations.cpp:11:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
11 | 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:21:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
21 | for (int i=0;i<u.size();i++){
| ~^~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:33:17: 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<c.size();i++){
| ~^~~~~~~~~
stations.cpp:39:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
39 | for (int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:44:1: warning: control reaches end of non-void function [-Wreturn-type]
44 | }
| ^