Compilare: user.cpp: In member function ‘std::vector<double> Edge::intersect(const Edge&)’: user.cpp:36:20: warning: unused variable ‘t’ [-Wunused-variable] double t = -1. * c / (1. * b); ^ user.cpp: In function ‘std::pair<double, double> query(int)’: user.cpp:144:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (intidx != events.size() - 1) { ^ user.cpp: In function ‘int main()’: user.cpp:164:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < v.size(); k++) { ^ user.cpp:176:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < events.size(); i++) { ^ user.cpp:152:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mst.in", "r", stdin); ^ user.cpp:153:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mst.out", "w", stdout); ^ user.cpp:155:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:157:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &u, &v, &a, &b, &c); ^ user.cpp: In member function ‘std::vector<double> Edge::intersect(const Edge&)’: user.cpp:47:5: warning: control reaches end of non-void function [-Wreturn-type] } ^