PLEASE SOLVE THE PROBLEM IN PYTHON

Question

You are given a dummy headed singly circular linked list. convert it to a doubly linked list. You cannon create any separate linked list. Can only use def listTransform(head) and countNode() method.

Answer 1

_LAST is the last node in the list;

_FIRST is the first node in the list;

Simply do:

_LIST->next = NULL

_FIRST->prev=NULL

you may now treat it as a doubly linked list, that is NOT circular,

as the links which make it circle have been broken (set to NULL)

Why would one want to sacrifice this type of nice feature ?