Compilare: user.cpp: In function ‘void read()’: user.cpp:49:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<c.size(); ++i) ^ user.cpp: In function ‘void bfs()’: user.cpp:77:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^