Circular Linked List

Preview

1. What is a circular linked list and how does it differ from a regular linked list?
2. What are the advantages and disadvantages of using a circular linked list over a regular linked list?
3. What is the time complexity for searching, inserting and deleting nodes in a circular linked list?
4. How do you convert a regular linked list to a circular linked list?
5. What are some real-life applications where a circular linked list is useful?

Explain

A circular linked list is a type of linked list in which the last node of the list points to the first node, creating a circular sequence. This means that traversal of the list can start from any node, but it always ends up back at the same node where it began.

Example:
Let’s take an example of a circular linked list that contains three nodes. The first node contains the data value of “A,” the second node contains “B,” and the third node contains “C.” Each node in the list contains a pointer to the next node, and the last node in the list points back to the first node, forming a circular sequence.

The structure of the circular linked list will look like:

(A)->(B)->(C)->(A)

Here, the pointer of node “A” points towards node “B,” the pointer of “B” points towards “C,” and the pointer of “C” points towards “A.”

In this manner, the operations of inserting, deleting, or traversing elements in a circular linked list, work similar to that of a normal singly linked list. However, it is important to keep in mind that the linked list is circular, and care must be taken to ensure that the traversal does not enter an infinite loop by going in circles.

Keypoint

1. A circular linked list is a linked list in which the last node points back to the first node.
2. It is a dynamic data structure that is useful when the data items need to be accessed in a loop.
3. The operations that can be performed on a circular linked list include insertion, deletion, traversal, and searching.
4. The circular linked list has a property of infinite size since it can continue forever.
5. Deletion of nodes from a circular linked list involves updating the links of the previous and next nodes to avoid broken links.
6. Insertion of nodes in a circular linked list involves updating the links of the previous and next nodes to ensure continuity.
7. A circular linked list can be implemented using a singly linked list or a doubly linked list.
8. A circular linked list can be used to implement circular buffers, memory allocation in operating systems, and round-robin scheduling.

Review

1. What is a circular linked list?

Answer: A circular linked list is a data structure that organizes data elements in a circular sequence, where the last element points to the first element, forming a closed loop.

2. How is the insertion operation performed in a circular linked list?

Answer: The insertion operation in a circular linked list involves creating a new node, updating its pointers to link it with adjacent nodes, and updating the pointers of the previous and next nodes to point to the new node.

3. What is the advantage of using a circular linked list over a linear linked list?

Answer: One advantage of using a circular linked list over a linear linked list is that it allows for easy traversal from the last element to the first element without having to traverse through the entire list.

4. Can a circular linked list be empty?

Answer: Yes, a circular linked list can be empty, where the head/tail nodes point to null, indicating an empty list.

5. How is the deletion operation performed in a circular linked list?

Answer: The deletion operation in a circular linked list involves updating the pointers of the adjacent nodes to bypass the node to be deleted, freeing the memory space occupied by the deleted node, and updating the pointers of the head/tail nodes to point to the correct nodes in the list.