Lecture 168:-  About Linked List

 

A linked list is a data structure that consists of a sequence of elements called "nodes," each of which contains two parts: a data field to store the element's value and a reference (or pointer) to the next node in the sequence. The last node typically has a reference set to NULL, indicating the end of the list. Linked lists offer dynamic memory allocation, making them flexible and efficient for handling varying amounts of data.

There are several types of linked lists, each with its own characteristics:

1. Singly Linked List: In a singly linked list, each node points only to the next node in the sequence. It forms a unidirectional chain of nodes, starting from the head (the first node) and ending at the tail (the last node).
2. Doubly Linked List: A doubly linked list extends the concept of a singly linked list by having each node point to both the next and the previous node in the sequence. This bidirectional linkage allows for easier traversal in both directions.
3. Circular Linked List: In a circular linked list, the last node's reference points back to the head node, creating a circular structure. This means that the list does not have a distinct beginning or end and can be traversed indefinitely.

Linked lists have various applications and are advantageous for specific scenarios:

• Dynamic Memory Management: Linked lists allow efficient allocation and deallocation of memory during runtime, as they do not require contiguous memory blocks like arrays.
• Efficient Insertions and Deletions: Adding or removing elements from a linked list is efficient, as it involves updating pointers, rather than shifting elements, which is the case with arrays.
• Flexible Size: Linked lists can change their size dynamically, making them suitable for handling data of varying or unknown sizes.

However, linked lists also have some disadvantages:

• Extra Memory Overhead: Each node in a linked list requires additional memory for storing the reference to the next node, leading to a slightly higher memory overhead compared to arrays.
• Sequential Access: Random access is not efficient in linked lists. To access an element at a particular index, you need to traverse the list from the beginning.

In summary, linked lists provide a versatile and efficient data structure for handling dynamic data and frequent insertions and deletions. The specific type of linked list used depends on the requirements of the problem at hand.