Compilare: user.cpp: In member function ‘int trie::next(char)’: user.cpp:30:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ch.size();i++) if(c==ch[i]) return to[i]; ^ user.cpp: In function ‘void Push(int, std::string)’: user.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) w=Trie[w].next(s[i]); ^