Linked List in Data Structure

What is a Linked List?

A linked list is a linear collection of elements known as nodes, each of which carries a connection to the next node. You can traverse a linked list in any way, beginning at any node. It is used to implement data structures such as queues and stacks.

Linked list representation in Data Structures

A linked list is a connection of nodes, with each node pointing to the next node in the list.

Basic Terms for Linked List

• Head: A pointer to the first node in a linked list.
• Node: A data structure that includes a pointer to the next node.
• Data: Information is stored within each node.
• Next pointer: Points to the next node in the linked list.

Types of Linked Lists in Data Structures

There are generally three types of linked lists:

1. Singly-linked list
2. Doubly linked list
3. Circular linked list

Singly-linked list

A singly linked list is a linear data structure in which each member, known as a node, refers to the next node in the sequence, allowing traversal in only one direction.

Doubly linked list

Similar to a singly linked list, each node has two pointers, one to the next node and one to the previous node, allowing bidirectional traversal.

Circular linked list

A linked list in which the last node points back to the first node, resulting in a circular structure. This is useful for applications that require continuous looping or when the end of the list must connect to the beginning.

Basic Operations of Linked List

• Traversal: Access each element of the linked list.
• Insertion: Add a new element to the linked list.
• Deletion: Removes existing items.
• Search: Find a node in the linked list.
• Sort: Sort the nodes in the linked list.

Complexity Analysis of Linked List Operations

Time Complexity

Space Complexity

All operations on the linked list have a space complexity of O(n).

Applications of Linked List

• Data Structures: Linked lists are utilized in stacks, queues, graphs, and hash tables.
• Memory Allocation: Memory is assigned from a linked list of free blocks, making maintenance easier.
• File Systems: Effectively represent directories and files in file systems.
• Music/Video Players: Control playlists and song sequences.
• Graphs: Adjacency lists use linked lists to hold neighboring vertices.
• Games: Represent game boards, which help with game state management.

Advantages of Linked List

• Dynamic: Resizable during runtime to accommodate limitless element modifications.
• Efficient manipulation: Simple pointer changes allow for easy element addition and removal.
• Flexibility: Suitable for stacks, queues, and hash table implementations.
• Memory Efficiency: Changes size dynamically to optimize memory use.
• Easy Implementation: Simple structure and functionality allow for quick setup.

Disadvantages of Linked List

• Memory Consumption: Since linked lists use pointers frequently, they use more memory and are more sophisticated.
• Traversal: Accessing individual nodes in linked lists necessitates iterating through all nodes from the start, which is inefficient for long lists.
• No Random Access: Linked lists do not provide direct access to specific nodes, making them unsuitable for applications that demand fast element access.
• Cache Misses: Linked lists are prone to cache misses, which slow down programs that regularly retrieve data from them.
• Search: Linked lists are inefficient for searching huge data sets, which are better suited to structures such as trees or hash tables.