Compilare: main.cpp: In member function 'void Trie::dfs(Node*, std::string&, int)': main.cpp:30:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 30 | if (level==s.size()) | ~~~~~^~~~~~~~~~ main.cpp: In member function 'void Trie::insert(std::string&)': main.cpp:53:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 53 | for (int i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp: In member function 'int Trie::longest_prefix(std::string&)': main.cpp:75:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 75 | for (int i=0; i<s.size(); i++) | ~^~~~~~~~~ main.cpp: In member function 'int Trie::count(std::string&)': main.cpp:91:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 91 | for (int i=0; i<s.size(); i++) | ~^~~~~~~~~