Compilare: user.cpp: In function ‘std::pair<double, double> query(int)’: user.cpp:157:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (intidx != events.size() - 1) { ^ user.cpp: In function ‘int main()’: user.cpp:178:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < v.size(); k++) { ^ user.cpp:190:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < events.size(); i++) { ^ user.cpp:165:34: 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:166:36: 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:168:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:170:52: 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); ^