Compilare: main.cpp: In member function 'bool Trie::find(std::__cxx11::string, int, int)': main.cpp:61:23: warning: array subscript has type 'char' [-Wchar-subscripts] if(curr -> nxt[s[i]] - 'a' == nullptr) ^ main.cpp: In function 'int main()': main.cpp:89:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int l = 0; l < s.size(); l++) ~~^~~~~~~~~~ main.cpp:90:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int r = l; r < s.size() && r - l + 1 <= 60; r++) ~~^~~~~~~~~~ main.cpp:99:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int l = 0; l < s.size(); l++) ~~^~~~~~~~~~ main.cpp:100:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int r = l; r < s.size(); r++) ~~^~~~~~~~~~