Compilare: user.cpp: In function ‘bool check_vertice(int, int)’: user.cpp:17:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < adj[x].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:49:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < adj[k].size(); i++) ^