# What Are the Types of Linked List in Data Structure?

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Angela Bailey

A linked list is a popular data structure used in computer programming. It is a collection of nodes that are connected to each other through pointers.

Each node contains a data element and a reference to the next node in the sequence. Linked lists offer dynamic memory allocation and efficient insertion and deletion operations compared to arrays.

There are several types of linked lists, each with its own unique characteristics and use cases. Let’s explore some of the commonly used types:

The singly linked list is the simplest form of a linked list. In this type, each node contains data and a single pointer that points to the next node in the sequence. The last node’s pointer points to null, indicating the end of the list.

In HTML, you can represent a singly linked list using an unordered list (

) with list items (

• ). Here’s an example:

• Data 1
• Data 2
• Data 3

A doubly linked list extends the functionality of a singly linked list by including an additional pointer that points to the previous node. This enables traversal in both directions, forward and backward.

To visually represent a doubly linked list, we can use nested unordered lists within another unordered list:

• Data 1

• Previous: null
• Next: Data 2
• Data 2

• Previous: Data 1
• Next: Data 3
• Data 3

• Previous: Data 2
• Next: null

A circular linked list is a variation of the singly or doubly linked list in which the last node’s pointer points back to the first node (for a singly circular linked list) or both the first and last nodes (for a doubly circular linked list). This creates a circular structure.

To visually represent a circular linked list, we can use an unordered list with an additional arrow indicating the circular connection:

• Data 1 →
• Data 2 →
• Data 3 →
• Data 1 (circular)

### Skip List

A skip list is an advanced data structure that uses multiple layers of linked lists to achieve efficient search, insertion, and deletion operations. Each layer acts as an express lane to skip over several nodes in the lower layers, reducing the average time complexity.

The visual representation of a skip list can be complex due to its layered structure. However, we can represent it using nested unordered lists with appropriate indentation:

• Data A
• Data C
• Data E (express lane)
• Data F (express lane)
• Data D
• Data F (express lane) Data G (express lane)
• Data B
• Data D
• Data F (express lane)
• Data G (express lane)
• Data E
Data G (express lane) Data H (express lane)

I hope this article has provided you with valuable insights into the types of linked lists in data structures. Happy coding!