stations.cpp: In function 'int build(int, int)':
stations.cpp:17:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
17 | for(int i=0;i<point[now].to.size();i++){
| ~^~~~~~~~~~~~~~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:57:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
57 | for(int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:71:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
71 | for(int i=1;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:72:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
72 | ls=c[i];rs=(i==c.size()-1?s:c[i+1]-1);
| ~^~~~~~~~~~~~
stations.cpp:82:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
82 | for(int i=1;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:87:1: warning: control reaches end of non-void function [-Wreturn-type]
87 | }
| ^