Compilare: main.cpp: In member function 'void Trie::insert(std::__cxx11::string)': main.cpp:42:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.length(); i++) { ~~^~~~~~~~~~~~ main.cpp: In member function 'void Trie::remove(std::__cxx11::string)': main.cpp:54:14: warning: unused variable 'rem' [-Wunused-variable] bool rem = _remove(s, 0, curr); ^~~ main.cpp: In member function 'bool Trie::_remove(std::__cxx11::string, int, TrieNode*)': main.cpp:58:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == s.length() - 1) { ~~^~~~~~~~~~~~~~~~~ main.cpp: In member function 'int Trie::count(std::__cxx11::string)': main.cpp:80:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.length(); i++) { ~~^~~~~~~~~~~~ main.cpp: In member function 'int Trie::longest_prefix(std::__cxx11::string)': main.cpp:92:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.length(); i++) { ~~^~~~~~~~~~~~ main.cpp: In member function 'bool Trie::_remove(std::__cxx11::string, int, TrieNode*)': main.cpp:76:5: warning: control reaches end of non-void function [-Wreturn-type] } ^