Compilare: user.cpp: In function ‘void bfs()’: user.cpp:30:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:77:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();++i) ^