Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:23:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[act].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:35:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("amici.in", "r", stdin); ^ user.cpp:36:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("amici.out", "w", stdout); ^ user.cpp:37:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^ user.cpp:41:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] { scanf("%d %d", &n, &m); ^ user.cpp:46:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] { scanf("%d %d", &a, &b); ^