📝 Linked List – Introduction and Types Explained Simply

 


Introduction

A Linked List is a linear data structure used to store a collection of elements called nodes. Unlike arrays, linked lists do not store elements in contiguous memory locations. Each node contains two parts: data and a link (pointer) to the next node. Linked List is an important topic in Data Structures exams, interviews, and programming.

What is a Linked List?

A Linked List is a collection of nodes where:

  • Each node stores data

  • Each node contains a pointer to the next node

  • The first node is called the head

  • The last node points to NULL

Because nodes are connected using pointers, linked lists are dynamic and flexible.

Structure of a Node

Each node in a linked list has:

  1. Data part – stores the value

  2. Next pointer – stores the address of the next node

| Data | Next |

Why Linked List is Needed

Arrays have some limitations:

  • Fixed size

  • Memory wastage

  • Costly insertion and deletion

Linked Lists solve these problems by allowing:

  • Dynamic memory allocation

  • Easy insertion and deletion

  • Efficient memory usage

Types of Linked List

1️⃣ Singly Linked List

In a Singly Linked List:

  • Each node points to the next node

  • Traversal is only in one direction

Example:

10 → 20 → 30 → NULL

Advantages

  • Simple implementation

  • Less memory usage

Disadvantages

  • Cannot traverse backward

2️⃣ Doubly Linked List

In a Doubly Linked List:

  • Each node has two pointers

  • One points to the next node

  • One points to the previous node

Example:

NULL ← 10 ↔ 20 ↔ 30 → NULL

Advantages

  • Bidirectional traversal

  • Easy deletion

Disadvantages

  • More memory required

3️⃣ Circular Linked List

In a Circular Linked List:

  • The last node points back to the first node

  • No NULL pointer

Example:

10 → 20 → 30 → (back to 10)

Advantages

  • Efficient memory usage

  • Suitable for continuous operations

Disadvantages

  • More complex logic

Operations on Linked List

  • Insertion

  • Deletion

  • Traversal

  • Searching

Advantages of Linked List

  • Dynamic size

  • Efficient insertion and deletion

  • No memory wastage

Disadvantages of Linked List

  • Extra memory for pointers

  • Slower access compared to arrays

  • No random access

Applications of Linked List

  • Dynamic memory management

  • Implementation of stack and queue

  • Music playlist

  • Browser navigation

Conclusion

Linked List is a flexible and dynamic data structure that overcomes the limitations of arrays. Understanding the types of linked lists and their operations is essential for data structures exams and real-world applications.

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