What is the difference between a singly linked list and a doubly linked list in terms of node pointers and traversal efficiency?

• A. Doubly linked lists have a next pointer only.
• B. Singly linked list has a next pointer only and traversal is forward; doubly linked lists have next and prev pointers enabling bidirectional traversal and easier deletions, at the cost of extra memory.
• C. Singly traverses backwards; doubly traverses forward.
• D. Doubly linked lists are smaller in memory than singly.

Answer: (B)

Pointers stored in each node and how that affects traversal and deletions. In a singly linked list, each node holds a reference to the next node only, so you can move forward through the list but you can’t go backward directly. Deleting or inserting in the middle is more awkward because you usually need the previous node, which requires traversing from the head to find it. In a doubly linked list, every node has both next and prev references, allowing traversal in either direction and making deletions easier since you can reconnect neighbors without a full pass. The trade-off is extra memory for the extra pointer per node and a bit more complexity in updates. The other statements misstate the pointer setup or traversal/memory characteristics.