Compilare: user.cpp: In function ‘void find_cycle(int, int, int)’: user.cpp:13:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[nod].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:24:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tric.in","r",stdin); ^ user.cpp:25:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tric.out","w",stdout); ^ user.cpp:27:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:30:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^