Compilare: user.cpp: In function ‘void erase(int, int)’: user.cpp:31:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[a].size();++i) ^ user.cpp: In function ‘void df(int)’: user.cpp:52:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[k].size();++i) ^ user.cpp: In function ‘void write()’: user.cpp:124:9: warning: unused variable ‘gata’ [-Wunused-variable] int gata = 0; ^