Compilare: main.cpp: In function 'void Insert(Trie*, std::__cxx11::string)': main.cpp:17:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp: In function 'void Delete(Trie*, std::__cxx11::string)': main.cpp:34:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp:39:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p->children.size()>1 || (p->num && i!=s.size()-1)) ~^~~~~~~~~~~~ main.cpp:52:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pi<s.size()) ~~^~~~~~~~~ main.cpp:54:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pi+1==s.size()) ~~~~^~~~~~~~~~ main.cpp: In function 'int Find(Trie*, std::__cxx11::string)': main.cpp:70:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ~^~~~~~~~~ main.cpp: In function 'int LongestPrefix(Trie*, std::__cxx11::string)': main.cpp:87:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ~^~~~~~~~~