stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:18:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
18 | for (int i = 0; i < u.size(); i++) {
| ~~^~~~~~~~~~
stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:29:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
29 | for (int i = 0; i < c.size() - 1; i++) if (c[i] <= t && t < c[i + 1]) return c[i];
| ~~^~~~~~~~~~~~~~
stations.cpp:30:1: warning: control reaches end of non-void function [-Wreturn-type]
30 | }
| ^