Compilare: user.cpp: In static member function ‘static convolution::Modular convolution::Modular::root(int)’: user.cpp:91:14: warning: unused variable ‘ans’ [-Wunused-variable] auto ans = root; ^ user.cpp: In function ‘void read(std::vector<int>&)’: user.cpp:252:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (a.size() < x+1) ^ user.cpp: In function ‘void print(std::vector<int>&)’: user.cpp:259:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); ++i) { ^