stations.cpp: In function 'void dfs(int, int, int)':
stations.cpp:11:20: 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 < edge[u].size(); i++) if (edge[u][i] != v) dfs(edge[u][i],u,d+1);
| ~~^~~~~~~~~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:31:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | for (int i = 0; i < c.size()-1; i++) if (t <= c[i]) return c[i];
| ~~^~~~~~~~~~~~
stations.cpp:34:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
34 | for (int i = 1; i < c.size()-1; i++) if (t < c[i]) return c[i-1];
| ~~^~~~~~~~~~~~