Compilare: user.cpp: In function ‘void BFS(int, int, bool)’: user.cpp:42:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( d = 0 ; d < G[vertex].size() ; d ++ ) ^ user.cpp: In function ‘void Read()’: user.cpp:25:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d%d%d" , &n , &m , &x , &y ); ^ user.cpp:28:59: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d%d" , &a , &b ) , G[a].pb(b),G[b].pb(a); ^ user.cpp: In function ‘int main()’: user.cpp:78:33: 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:79:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( OUT , "w" , stdout ); ^