Updated March 6, 2023
Introduction to Linked List -Data Structure
The following article provides an outline for Linked List Types. A Linked List is defined as a series of data structures consisting of items that are associated together via links. This Linked list is a type of linear data structure where data elements are linked in a list using pointers. Linked List is known to be the next mostly implemented data structure type after the array. Basically, the linked list includes nodes where every node consists of a data field and a link referring to the next node in the provided list.
The linked list comprises of few standard operations such as Traversal, Insertion, Searching, Deletion, Updating, Merging, and Sorting applied on the nodes and lists. Also, the Linked list is a dynamic data structure that has the feature to develop and shrink at the runtime by allotting and deallocating memory.
Various Linked List Types
Given below are various types of Linked List used for collecting and keeping the data items.
Also, the following are the vital terms for understanding the perception of Linked List:
- Link: Every link of the Linked List stores data known as elements.
- Next: Every link of the Linked List includes a link to the succeeding link known as Next.
- Linked list: This list comprises the connection link to the initial link known as First.
Below are the Linked List types explained in detail:
1. Singly or, Simple Linked List
In this type, item navigation is simply forward. This is the simplest Linked List kind where each node consists few data and a pointer pointing to the next node of a similar data type. Here, the line that the node consists of the pointer to the next node defines that the address of the next node is stored by the node. This singly Linked List permits traversal of the info only in one way. In the linked list the pointer which contains the address of the primary node is called as a head pointer. In this singly linked list, the last node has no pointer to any node hence, this link part holds the NULL value.
You can view the diagrammatic representation of the singly linked list as follows:
2. Doubly Linked List
In this type, item navigation can be performed either forward or backward. Hence, this type is also known as a two-way Linked list, which is a more difficult kind of linked list consisting a pointer to the next node as well as a preceding node in the sequence. So, it includes three sections that are data, a pointer referring to the next node, and also a pointer referring to the preceding node. This technique allows us for traversing the list as well as in the backward direction. You can view the diagrammatic representation of the doubly linked list as follows:
If the node to be removed is provided, then the delete operation is found to be more resourceful. Also, if the node is provided before which the operation of insertion should take place then the insertion operation tends to be more effective.
3. Circular Linked List
In this type, the preceding item includes a link of the primary element as next and the primary element also includes a link to the preceding element as previous. This means the last (preceding) node holds the pointer to the first node of the linked list. If the traversal takes place in a circular linked list then, one can start at any node as well as traverse the list following any direction backward and forward unless the same node is reached from where the traversal was begun. Thus, in a circular list there is no starting and end node therefore, it creates a circular loop. You can view the diagrammatic representation of the circular linked list as follows:
This circular linked list is a significant data structure when a user needs a list that is to be retrieved in a loop or circle. Operations is difficult in circular in comparison to a singly list.
4. Doubly Circular Linked List
In this type, the linked list item consists of a link to the next along with the previous node in the series. This is an extended type of previous Linked list i.e. circular linked list. It is a two-way circular linked list which is a more complex kind of Linked List containing a pointer to the succeeding as well as the preceding node in the series. We can have the difference between the doubly linked list and circular doubly list similar to the difference between the singly list and circular list. The circular doubly linked list has no null in the preceding field of the primary node. In this list, the last node is connected to the primary node holding the link.
There may be other types like Header Linked list and Multi Linked list. Thus, a linked list can be defined as a linear collection of data items whose order is not provided by their physical placement in memory but here every item references to the next one using the pointers. It has time complexity as O(n). There are few variables applied in the Linked list such as NULL, AVAIL, START, PTR, and NEW NODE.
The Linked List has various applications such as executing arithmetic procedures in the long integer, maintaining directory names, moving songs next previous in a music player or same with the image viewer, undo operation in Photoshop and Word, applying hash tables, manipulation, and representation of polynomial, etc.It has a disadvantage that a linked list raises complexities if it operates reverse traversal.
This Linked List can be said as a technique to collect and store identical data items. The data structure Linked List provides easy application of other data structures like queues and stack. With different Linked List types, the Linked List makes insertion as well as deletion operations of nodes actually easier. Also, with the Linked List, the memory is not wasted as the size can be increased or decreased of the Linked List at runtime.
This is a guide to Linked List Types. Here we discuss the introduction and various linked list types for the better understanding. You may also have a look at the following articles to learn more –