UGC NET CSE | December 2004 | Part 2 | Question: 24

Question

What operation is supported in constant time by the doubly linked list, but not by the singly linked list ?

• A. Advance

• B. Backup

• C. First

• D. Retrieve

Answer 1

In singly linked list we only goes to forward node  we can't goes back to  backward node because we only have forward pointer which point next node of linked list  but if we want we have to start from head(first node) it may take O(N) time

but in case of doubly linked list we can go to backward node by backward pointer it take O(1).

answer B