Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:26:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[y].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:64:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<Q[i].size();++j) ^