{"id":22295,"date":"2022-11-02T10:16:52","date_gmt":"2022-11-02T17:16:52","guid":{"rendered":"https:\/\/coderpad.io\/?p=22295"},"modified":"2023-06-05T13:56:35","modified_gmt":"2023-06-05T20:56:35","slug":"an-introduction-to-linked-list-data-structures","status":"publish","type":"post","link":"https:\/\/coderpad.io\/blog\/development\/an-introduction-to-linked-list-data-structures\/","title":{"rendered":"An Introduction to Linked List Data Structures"},"content":{"rendered":"\n

Linked lists are one of the fundamental linear data structures<\/a> alongside stacks, queues, arrays, and lists.<\/p>\n\n\n\n

A linked list is a continuous list of nodes where a node is a block structure housing the node value and a pointer (or memory) address to the next node. Each node from the head node has a next<\/code> pointer that keeps the address of the next node till it gets to the last node, which points to nothing.<\/p>\n\n\n\n

Linked lists are used in web browsers to keep track of web pages visited and moves in multi-player board games. Linked lists also find usage in implementing other linear data structures and graphs, dynamic memory allocation, and performing arithmetic operations on long integers.<\/p>\n\n\n\n

The connection from one node to another node differentiates linked lists from a regular list or array. Unlike the linked lists, arrays don’t keep track of their next or other values.<\/p>\n\n\n\n

Here is a visual representation of a linked list:<\/p>\n\n\n\n

\"A
A linked list with 4 nodes. Each node points to another node.The last node always points to NULL, except for circular linked lists.<\/figcaption><\/figure>\n\n\n\n

Types of Linked Lists<\/strong><\/p>\n\n\n\n

The last node always points to NULL, except for circular linked lists.<\/em><\/p>\n\n\n\n

Types of Linked Lists<\/strong><\/h2>\n\n\n\n

There are three types of linked lists:<\/p>\n\n\n\n

    \n
  1. Singly-linked list<\/li>\n\n\n\n
  2. Doubly linked list<\/li>\n\n\n\n
  3. Circular linked list<\/li>\n<\/ol>\n\n\n\n

    You can derive other linked lists from the basic ones, e.g., circular doubly linked lists. This article teaches you how to implement the singly and doubly linked list and briefly discusses the circular linked list.<\/p>\n\n\n\n

    \n

    \ud83d\udca1 In this article, we\u2019ll use the Python programming language for the implementations.<\/p>\n<\/blockquote>\n\n\n\n

    Singly-linked list<\/h2>\n\n\n\n

    You\u2019re tasked with building a tool to retrieve documents connected to each other but<\/strong> stored at random memory locations. You\u2019re puzzled as to what data structure to use to fit this use case, as arrays store documents sequentially. The good news is that you can use the singly linked list for this task.<\/p>\n\n\n\n

    A singly linked list is defined by its node. A singly linked list node has a value and the next pointer. The diagram below is an example of a singly linked list.<\/p>\n\n\n\n

    \"A
    A linked list with 4 nodes. Each node points to another node. The last node always points to NULL, except for circular linked lists.<\/figcaption><\/figure>\n\n\n\n

    To implement the linked list, start with the node class:<\/p>\n\n\n

    class<\/span> Node<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, value)<\/span> -> None<\/span>:<\/span>\n        self.value = value\n        self.next = None<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
    In the code block above, the node class comprises two attributes:<\/p>\n\n\n\n