Compilare: user.cpp: In function ‘void get_all_codes(const string&, int, std::set<long long unsigned int>*)’: user.cpp:15:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < s.size(); ++k) { ^ user.cpp: In function ‘int main()’: user.cpp:48:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j <= min(size_t(60), s[i].size()); ++j) { ^ user.cpp:54:53: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j <= min(size_t(60), s[i].size()); ++j) { ^