Compilare: main.cpp: In member function 'void Trie::add(Trie::Node*&, std::__cxx11::string, int, int)': main.cpp:36:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k == s.size()) ~~^~~~~~~~~~~ main.cpp: In function 'bool OK(int)': main.cpp:49:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < v.size(); i++){ ~~^~~~~~~~~~ main.cpp:52:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(u > nodes[x].size() - 1) ~~^~~~~~~~~~~~~~~~~~~~~