Compilare: user.cpp: In function ‘int main()’: user.cpp:20:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=1; i<=N-1; i++) ^ user.cpp:34:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[node].size(); i++) ^ user.cpp:50:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<v[node].size(); i++) ^