Solution

The correct answer is Both A and R are true and R is the correct explanation of A

Key PointsIn a doubly linked list, each node typically maintains two references (or pointers): one to the next node and one to the previous node. However, it is indeed possible to create a doubly linked list using only one pointer per node. This can be achieved by storing the XOR of the addresses of the previous node and the next node in place of the two pointers. This technique is called XOR-linking.

Here's how it works:

• The XOR operation has a property whereby (A XOR B) XOR A equals B and (A XOR B) XOR B equals A.
• For each node, you are storing (address of previous node) XOR (address of next node). To traverse nodes in this list forward or backward, you start with a pointer to the current node and a pointer to its predecessor (for forward traversal) or its successor (for backward traversal). Then you can get the address of the next node or the previous node with XOR operations.
• So if you're traversing forward, your next node is (address of predecessor) XOR (current node's XOR value). To traverse backward, (address of successor) XOR (current node's XOR value) gives you the address of the previous node.

Using this technique you can successfully traverse both forward and backward in the list using only one pointer in each node. So, both the Assertion A and the Reason R are true and R is indeed a correct explanation of A.