/in/foo.cc: In function 'void insert(const char*)':
/in/foo.cc:23:32: warning: array subscript has type 'char' [-Wchar-subscripts]
         if (ch[p][cvt_ci[str[i]]] == 0)
                                ^
/in/foo.cc:24:32: warning: array subscript has type 'char' [-Wchar-subscripts]
             ch[p][cvt_ci[str[i]]] = ++ptot;
                                ^
/in/foo.cc:25:32: warning: array subscript has type 'char' [-Wchar-subscripts]
         p = ch[p][cvt_ci[str[i]]];
                                ^
/in/foo.cc: In function 'int search(const char*)':
/in/foo.cc:54:37: warning: array subscript has type 'char' [-Wchar-subscripts]
         int id = cvt_ci[str[dep + 1]];
                                     ^