Create a Circular Singly Linked List in DSA Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Circular Singly Linked List?

A Circular Singly Linked List is a linked list where the last node points back to the first node, forming a circle. There is no null at the end.

beginner

How do you identify the last node in a Circular Singly Linked List?

The last node is the one whose next pointer points back to the head (first node) of the list.

intermediate

Why use a Circular Singly Linked List instead of a regular singly linked list?

It allows continuous traversal from any node without stopping, useful for applications like round-robin scheduling or buffering.

intermediate

What is the key difference in node insertion between a regular singly linked list and a circular singly linked list?

In a circular singly linked list, when inserting the first node, its next pointer must point to itself to maintain the circle.

beginner

Show the Python code snippet to create a single node circular singly linked list.

class Node:
    def __init__(self, data):
        self.data = data
        self.next = self

head = Node(10)  # Single node points to itself

In a circular singly linked list, what does the last node's next pointer point to?

A Null

B Itself

C The first node

D The second node

The last node's next pointer points back to the first node to form a circle.

What is the main advantage of a circular singly linked list?

A No need to check for null to end traversal

B Uses less memory

C Faster search

D Simpler insertion at head

Traversal can continue indefinitely without checking for null because the list loops back to the start.

When creating the first node in a circular singly linked list, what should its next pointer be set to?

A Itself

B Null

C Head

D None

The first node points to itself to maintain the circular structure.

Which of these is NOT a property of a circular singly linked list?

A Last node points to first node

B Has a null pointer at the end

C Each node has one next pointer

D Traversal can loop infinitely

Circular singly linked lists do not have a null pointer at the end.

How do you detect the end of traversal in a circular singly linked list?

A When next pointer points to itself

B When next pointer is null

C When data is None

D When you reach the head node again

Traversal ends when you come back to the head node, completing the circle.

Explain how to create a circular singly linked list with one node and why the next pointer points to itself.

Think about how to keep the list circular even with one node.

Describe the difference between a regular singly linked list and a circular singly linked list in terms of traversal and end condition.

Focus on what happens when you reach the last node.