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:55:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
55 | for(int i=0;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:69:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
69 | for(int i=1;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:70:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
70 | ls=c[i];rs=(i==c.size()-1?s:c[i+1]-1);
| ~^~~~~~~~~~~~
stations.cpp:80:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
80 | for(int i=1;i<c.size();i++){
| ~^~~~~~~~~
stations.cpp:85:1: warning: control reaches end of non-void function [-Wreturn-type]
85 | }
| ^