Compilare: user.cpp: In function ‘void DFS_visited(int)’: user.cpp:15:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<adj[node].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:37:22: warning: unused variable ‘x’ [-Wunused-variable] long long n, m , x, y; ^ user.cpp:37:25: warning: unused variable ‘y’ [-Wunused-variable] long long n, m , x, y; ^