Compilare: user.cpp: In function ‘int main()’: user.cpp:21:16: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(!seen[s[i]]){ ^ user.cpp:22:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] seen[s[i]] = 1; ^ user.cpp:27:28: warning: array subscript has type ‘char’ [-Wchar-subscripts] h.erase(h.find({freq[s[i]], s[i]})); ^ user.cpp:28:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] freq[s[i]]++; ^ user.cpp:29:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] h.insert({freq[s[i]], s[i]}); ^