DSA

Doubly Linked List

Learn about doubly linked lists, where each node points to both its next and previous neighbors, allowing bidirectional traversal.

By TechCoder TeamLast updated: 2026-06-02
In a Nutshell

Learn about doubly linked lists, where each node points to both its next and previous neighbors, allowing bidirectional traversal. This hands-on tutorial focuses on practical implementation of doubly linked list concepts.

Doubly Linked List

A Doubly Linked List (DLL) is a complex type of linked list in which each node contains a pointer to the next node as well as the previous node.

Structure of a Node

In a DLL, a node consists of three parts:

  1. Data: The value stored in the node.
  2. Next Pointer: Points to the next node in the sequence.
  3. Prev Pointer: Points to the previous node in the sequence.
class Node:
    def __init__(self, data):
        self.data = data
        self.next = None
        self.prev = None

Advantages of Doubly Linked List

  • Bidirectional Traversal: You can traverse in both forward and backward directions.
  • Easier Deletion: Deleting a node is more efficient if you have a pointer to the node to be deleted, as you don't need to find the previous node.
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Quiz

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Question 1 of 1

How much extra memory does a Doubly Linked List node use compared to a Singly Linked List node?

No extra memory
Memory for one extra pointer (prev)
Twice the memory
Memory for two extra pointers