Doubly Linked List in Data Structure

Level : Beginner
Mentor: Shailendra Chauhan
Duration : 00:03:00

What is a Doubly Linked List?

A doubly linked list (DLL) is a type of linked list in which each node has a pointer to both the previous and next node in the linked list.

Components of Doubly Linked List

A double-linked list is an upgrade of a singly linked list, with each node consisting of three components:

  • *prev: The address of the previous node
  • data: data item
  • a pointer *next: The address of the next node

Representation of a Doubly Linked List in Data Structures

A doubly linked list consists of nodes with a value and two pointers: prev and next, allowing bidirectional traversal. The head node's prev pointer points to NULL, while the tail node's next pointer points to NULL, indicating the start and end of the list.

Memory Representation of a Doubly Linked List

A Doubly Linked List is represented by linear arrays in memory, with each memory address storing three components:

  1. Data Value
  2. The memory address for the next element.
  3. The previous element's memory address.

Basic Operations of Doubly Linked List

  • Insertion: Insertion is the process of adding a new node to the beginning, end, or center of a list by modifying pointers accordingly.
  • Deletion: Removing a node from the list by changing the pointers to its neighboring nodes to ensure continuity.
  • Traversal: Traversal is the process of iterating across a list in either direction to access or modify the contents at each node.
  • Search: Finding a specific element by traversing the list until the desired data is discovered.

Complexity Analysis of Doubly Linked List Operations

Applications of Doubly Linked List

  • Browser History: Allows you to navigate backward and forth.
  • Music/Video Player: Allows playlist navigation in both ways.
  • Text Editor: Includes undo/redo and document history navigation.
  • Cache: Sorts data from most to least recently accessed.
  • Operating System: The operating system manages processes, allocates memory, and performs I/O activities.
  • File System: Organizes file directories for easy navigation.

Advantages of Doubly Linked List

  • Efficient Insertion & Deletion: Use pointer adjustments rather than shifting elements.
  • Bidirectional traversal: Allows movement in both forward and backward directions.
  • Flexibility: Adding and removing nodes without breaking the list.
  • Memory Efficiency: Memory is easily managed by adding and removing nodes.
  • Implementing Other Structures: Serves as a foundation for many tree structures.

Disadvantages of Doubly Linked List

  • More Memory Usage: Extra memory is required for the next and previous pointers.
  • Slower Operations: Access and search times are slower, particularly with larger listings.
  • Complex Traversal: Requires following both the previous and next pointers, which may be slower than other structures.
  • Code Complexity: Managing more pointers increases code complexity and the likelihood of errors.
  • Limited Suitability: Inefficient for algorithms that require random access.
  • Maintenance Challenges: Insertion and deletion necessitate the management of both pointers, which adds complexity and potential errors.
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