Difference between singly linked list and Doubly linked list in data structure

Difference between Singly linked list and Doubly linked list

Difference between Singly linked list and Doubly linked list in Java

Both Singly linked list and Doubly linked list are the implementation of Linked list in which every element of singly-linked list contains some data and a link to the next element, which allows to keep the structure. On the other hand, every node in a doubly-linked list also contains a link to the previous node.

The following are the important differences between a Singly linked list and Doubly linked list.

Sr. No.KeySingly linked listDoubly linked list

1	Complexity	In singly linked list the complexity of insertion and deletion at a known position is O[n]	In case od doubly linked list the complexity of insertion and deletion at a known position is O[1]
2	Internal implementation	In singly linked list implementation is such as where the node contains some data and a pointer to the next node in the list	While doubly linked list has some more complex implementation where the node contains some data and a pointer to the next as well as the previous node in the list
3	Order of elements	Singly linked list allows traversal elements only in one way.	Doubly linked list allows element two way traversal.
4	Usage	Singly linked list are generally used for implementation of stacks	On other hand doubly linked list can be used to implement stacks as well as heaps and binary trees.
5	Index performance	Singly linked list is preferred when we need to save memory and searching is not required as pointer of single index is stored.	If we need better performance while searching and memory is not a limitation in this case doubly linked list is more preferred.
6	Memory consumption	As singly linked list store pointer of only one node so consumes lesser memory.	On other hand Doubly linked list uses more memory per node[two pointers].

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.

What is Single Linked List

A linked list is a linear data structure that consists of a group of nodes in a sequence. A node or an element consists of data and the address of another node. A single linked list is a type of linked list.

A single linked list stores the data and the address of the next node in the sequence. As the nodes stores the address of the next node, the nodes are referring to each other. Therefore, it forms a structure similar to a chain. It is possible to perform operations such as inserting, deleting and traversing through the elements in a single linked list.

What is Double Linked List

Similar to a single linked list, a double linked list is also a type of linked list. It is also called a doubly linked list. It stores data and two addresses. These addresses are the address of the next node and the address of the previous node. As there are two references, it is possible to go forward and backward through elements in the double linked list. Furthermore, the programmer can perform operations such as inserting elements and deleting elements in a double linked list.

In addition to these two types, there is another linked list as a circular linked list. In this kind of list, the last node stores the address of the first node. Therefore, it forms a structure similar to a circular chain.

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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Difference Between Singly Linked List vs Doubly Linked List

What Is Singly Linked List?

It is the one of the variation of linked list in which operations of data items and elements are performed or executed in one way direction and it is defined for the storing of that object that further called as nodes and can be stored in memory randomly , there are two fields in singly linked list one is called where these data stores and the second is called pointer and these both link with the data to address them properly. Insertion, deletion and transversal operations are performed in singly linked list.