Compilare: main.cpp: In member function 'void Trie::add(Trie::Node*&, std::__cxx11::string, int, int, int)': main.cpp:50:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k == s.size()) { ~~^~~~~~~~~~~ main.cpp: In member function 'void Trie::insert(std::__cxx11::string, int)': main.cpp:71:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++){ ~~^~~~~~~~~~ main.cpp: In member function 'void Trie::erase(std::__cxx11::string)': main.cpp:76:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); i++){ ~~^~~~~~~~~~