Compilare: user.cpp: In function ‘void sort_top(int)’: user.cpp:12:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:31:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<V[nod].size();++i) ^