Compilare: main.cpp: In member function 'void Trie::insert(std::__cxx11::string&)': main.cpp:11:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<str.size(); ptr = ptr->son[str[i++]-'a']) ~^~~~~~~~~~~ main.cpp: In member function 'int Trie::compress(std::vector<std::vector<std::pair<int, int> > >&, bool*, int*)': main.cpp:20:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^