Compilare: user.cpp: In function ‘std::vector<int> find_cycle()’: user.cpp:153:13: warning: unused variable ‘el’ [-Wunused-variable] for (auto el : res) ^ user.cpp: In function ‘int main()’: user.cpp:91:46: warning: unused variable ‘_NN’ [-Wunused-variable] #define re(II, NN) for (int II(0), _NN(NN); (II) < (NN); ++(II)) ^ user.cpp:211:5: note: in expansion of macro ‘re’ re (j, 2) ^