Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:61:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G.size()&&ok;++j) ^ user.cpp:65:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G.size();++j) ^