Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:17:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v[nod].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:38:30: warning: iteration 21003u invokes undefined behavior [-Waggressive-loop-optimizations] lg[i] = lg[i / 2] + 1; ^ user.cpp:37:22: note: containing loop for(int i = 2; i <= Nmax; i++) ^