What is the advantage of a doubly linked list when compared to a singly linked?

Singly Linked List vs Doubly Linked List

Before looking at the differences between the singly linked list and doubly linked list, we first understand what is singly linked list and doubly linked list separately.

Introduction

In this article, we will explore the advantages, disadvantages as well as uses of doubly-linked lists.

We know that alinked listis a linear data structure that does not store the elements at contiguous memory locations. Rather, they are stored at random locations connected through pointers.

There are three types of linked lists:

• Singly Linked Lists
• Doubly linked lists
• Circular Linked Lists
  

First, let’s see what a doubly-linked list is and how it differs from a singly linked list?

In a singly-linked list, each node contains two pieces of information: data and pointer to the next node. But in the doubly linked list, each node contains an extra piece of information called the previous pointer. The previous pointer points to the previous node corresponding to each node in the linked list.

Difference Between Doubly linked list vs Singly linked list

• The singly linked list and doubly linked list is a type of linked list to arrange memory and information.
• The singly linked list and doubly linked list is part of dynamic data structure to avoid memory wastage and traverse using element in the list.
• The doubly linked list is a function that contains data, next node, and previous node simultaneously.
• The singly linked list is a function that contains data and the next node only.
• The singly linked list is a simple linked list to traverse one way from the first node to the next node.
• The doubly linked list is a complex linked list to traverse both ways from one node to another and vice versa.
• The singly linked list contains two parts, such as memory and pointer, but the last pointer becomes null.
• The doubly linked list contains three parts such as a previous pointer, memory node, and next pointer but the initial and last pointer becomes null.

Head to Head Comparison Between Doubly linked list vs Singly linked list (Infographics)

Below are the top differences between Doubly linked list vs Singly linked list

Key differences between Doubly linked list vs Singly linked list

Some of the key differences between Doubly linked list vs Singly linked list are given below:

• The doubly linked list is bidirectional because of two address pointer. Therefore, a singly linked list is unidirectional because of the one address pointer.
• The doubly linked list has occurred more memory space than the singly linked list.
• The singly linked list simple, whereas the doubly linked list, is a complex dynamic data structure of the list.
• The doubly linked list provides an empty head and tail pointer. Hence, a singly linked list provides an empty tail only.
• The doubly linked list more efficient than the singly list.
• The doubly linked list contains three parameters, and the singly linked list contains two parameters.
• The singly linked list image is given below.

• The doubly linked list image is given below.

• The doubly linked list gives time complexity O(1), whereas the singly linked list gives time complexity O(n).

Comparison table

• The doubly linked list is a complex function, and the singly linked list is a simple data structure.
• The comparison table is displayed features and descriptions of the singly linked list and doubly linked list.
• The below table is showing similarities and differences of the type of the linked list.

Features	doubly linked list	singly linked list
Definition	The doubly linked list is a complex linked list to manage memory with previous and next pointer.	The singly linked list is a simple linked list to manage memory with the next pointer.
Function	Organize dynamic data structure or values of the list.	Organize dynamic data structure or values of the list.
Parameter	Memory node Previous node Next node	Memory node Next node
Algorithm	The doubly linked list algorithm is below. 1) set Pointer = null 2) set New node = pointer 3) set Pointer = pointer -> next 4) set New node -> data = value 5) set New node -> previous = null 6) set New node -> next = start 7) set New head -> previous = New node 8) set New head = New node (continue procedure until last pointer) 9) last pointer -> null = tail 10) exit	The singly linked list algorithm is below. 1) set Pointer = null 2) set New node = pointer 3) set Pointer = pointer -> next 4) set New node -> data = value 5) set New node -> next = new head 6) set New head = New node (continue procedure until last pointer) 7) last pointer -> null = tail 8) exit
Description	The head pointer and tail are empty. Other nodes are including data.	The tail pointer is empty. The head and other nodes are including data.
direction	The node pointer addresses forward and reverses direction in the linked list. The doubly linked list supports bidirectional.	The node pointer addresses only the forward direction because of the next node. This linked list does not traverse the reverse direction. The doubly linked list supports unidirectional.
Memory space	The doubly linked list contains two addresses of the node. This variable takes 8-byte memory space.	The singly linked list contains one address of the node. This variable takes 4-byte memory spaces.
Time complexity	The time complexity of basic operation such as insert and delete of the list is O (1).	The time complexity of basic operation such as insert and delete of the list is Popular Course in this category Java Training (40 Courses, 29 Projects, 4 Quizzes)40 Online Courses | 29 Hands-on Projects | 285+ Hours | Verifiable Certificate of Completion | Lifetime Access | 4 Quizzes with Solutions 4.8 (12,280 ratings) Course Price View Course Related Courses Python Training Program (39 Courses, 13+ Projects)HTML Training (12 Courses, 19+ Projects, 4 Quizzes) O (n).
complexity	The doubly linked list is complex than a singly linked list to handle and operate data. It is difficult to manage data and its address.	The singly linked list is simple than a doubly-linked list to handle and operate data. It is easy to manage data and its address.
Operation	Insert the data in the list. Delete the data from the list. Traversing from each element Searching element from the linked list	Insert the data in the list. Delete the data from the list. Traversing from each element Searching element from the linked list
Advantages and limitations	Random access to the data is possible. The deletion is easy than the singly linked list. Uses more memory than the singly linked list. Easy to operate and handle any data.	Random access to the data is possible. The insertion process is easy than the doubly linked list. Use less memory. Cannot handle previous data of the list.
Implementation	Stack Hash table Binary tree	Stack Queue Fibonacci heap
Real-time Example	Navigation system to get backward and forward place. Operate Undo and Redo functionality in the application.	The queue of the people. Utensil or plate dispenser in the buffet.

Conclusion

• The singly linked list and doubly linked list make the application usable, handy, and manageable.
• The singly linked list and doubly linked list helps to manage and operate a list of data.

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What is the advantage of doubly linked list over singly linked list?