Compilare: user.cpp: In member function ‘int trie::next(char)’: user.cpp:38:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<TO.size();i++) if(c==TO[i].ch) return TO[i].to; ^ user.cpp: In function ‘void Push(int, std::string)’: user.cpp:49:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++) w=Trie[w].next(s[i]); ^