Compilare: main.cpp: In member function 'void Trie::Insert(std::__cxx11::string)': main.cpp:26:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) { ~~^~~~~~~~~~ main.cpp:28:27: warning: array subscript has type 'char' [-Wchar-subscripts] if(curr->nxt[c] == 0) { ^ main.cpp:30:28: warning: array subscript has type 'char' [-Wchar-subscripts] curr->nxt[c] = new Node(); ^ main.cpp:32:31: warning: array subscript has type 'char' [-Wchar-subscripts] curr = curr->nxt[c]; ^ main.cpp:33:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s.size() - 1) { ~~^~~~~~~~~~~~~~~ main.cpp: In member function 'void Trie::Delete(std::__cxx11::string)': main.cpp:42:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) { ~~^~~~~~~~~~ main.cpp:44:31: warning: array subscript has type 'char' [-Wchar-subscripts] curr = curr->nxt[c]; ^ main.cpp: In member function 'int Trie::CntAp(std::__cxx11::string)': main.cpp:58:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) { ~~^~~~~~~~~~ main.cpp:60:31: warning: array subscript has type 'char' [-Wchar-subscripts] curr = curr->nxt[c]; ^ main.cpp:61:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s.size() - 1) { ~~^~~~~~~~~~~~~~~ main.cpp: In member function 'int Trie::Prefix(std::__cxx11::string)': main.cpp:70:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) { ~~^~~~~~~~~~ main.cpp:72:27: warning: array subscript has type 'char' [-Wchar-subscripts] if(curr->nxt[c] == 0) break; ^ main.cpp:73:31: warning: array subscript has type 'char' [-Wchar-subscripts] curr = curr->nxt[c]; ^ main.cpp:75:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == s.size() - 1 && curr->val > 1) { ~~^~~~~~~~~~~~~~~