Compilare: user.cpp: In function ‘std::pair<long long int, std::vector<long long int> > divide(const std::vector<long long int>&)’: user.cpp:13:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < x.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:93:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) ^