Compilare: user.cpp: In function ‘void Solve()’: user.cpp:45:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < G[x].size() ; i ++ ) ^ user.cpp: In function ‘void Read()’: user.cpp:23:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &n , &m ); ^ user.cpp:26:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d%d" , &x , &y , &v ); ^ user.cpp: In function ‘int main()’: user.cpp:61:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen (IN,"r",stdin); ^ user.cpp:62:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen (OUT,"w",stdout); ^