Compilare: user.cpp: In function ‘int main()’: user.cpp:29:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(auto i:s1)++lit[0][i]; ^ user.cpp:30:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(auto i:s2)++lit[1][i]; ^ user.cpp:38:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s1.size();++i)a[i]=s1[i]; ^ user.cpp:39:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s2.size();++i)b[i]=s2[i]; ^