Advantages And Disadvantages Of Linked Lists Summed Up For You!

In Python, a list is an ordered sequence of values that can be of any type-string, integer, float, etc. It is a non-scalar type Data Structure. All the elements of a list are enclosed in square brackets, separated by commas. Elements in a list are arranged in a sequence beginning with index 0, just like characters in strings.

Now those who are well-versed with Data Structures in Python know that stacks allow insertion and deletion of objects at one end while, in queues, new objects are inserted at one end and deletion takes from the other end. Well, there exists a more flexible data structure called a linked list that allows the insertion and deletion of an object at an arbitrary position.

Lets' discuss the advantages and disadvantages of linked lists:

What are linked lists?

A linked list is a sequence of objects called nodes. The relative position of the objects in a linked list is maintained using the next link. Thus, a linked list comprises a number of objects, each of which contains a link to the next object (node).

For example:

Let us examine the link 1st as shown in the figure above. The first node of the linked list comprises an int object 20 and a next link, which is a reference to the second node in the linked list. In a similar manner, the second node consists of an int object 15 and the next link which in turn is the reference to the third node, and there is no next object ahead of it. Hence, it has an int object 25 and the next link refers to None.

We describe a class Node for dealing with the nodes of a linked list in a program. An instance of this class comprises two members, namely, data and next. A linked list may require the below mentioned functionalities:

Creating an empty linked list
Inserting a node at the beginning of a linked list
Deleting a node from the beginning of the linked list
Deleting a node with a particular value from the linked list
Inserting a node in a sorted linked list

Let's now proceed to discuss the advantages of linked lists over other Data Structures in Programming languages.

What are the advantages of Linked lists?

1) Dynamic growth/shrinkage

A linked list grows or shrinks dynamically depending upon how many items you want to add to your linked list. You don't have to specify its length initially. This makes them very useful when working with large amounts of data. For example, if you want to store names of people in a database then you will not have to worry about specifying their lengths because they would automatically increase according to the amount of information added.

2) Easy implementation

Data structures like stacks and queues can be easily implemented using linked lists. For example: In Python, stack implementation of linked list, push and pop operations are analogous to the following operations in a linked list: insertion at the beginning and deletion from the beginning. In queue implementation of the linked list, the method enqueue is used to insert at the rear end of the linked queue while the method dequeue deletes from the front end of the linked queue.

3) No space overhead

Since linked lists do not use any additional storage area apart from what is required by the actual elements themselves, they provide better performance than arrays. Also, unlike arrays, linked lists are dynamic meaning that we cannot predict beforehand how much memory will be needed. Therefore, we should always allocate enough memory before creating our linked list. If we try to create a linked list without allocating sufficient memory, we might get out of bounds exception.

4) Easy insertion and deletion

It's really simple to insert and remove the nodes. We don't have to move elements after they are added or removed, which is unlike what happens in Arrays. In the linked list, we only have to update the address at the next point of nodes.

What are the disadvantages of linked lists?

1) More consumption of memory

As compared to an array, the linked list requires more memory. A pointer is required to store the address of the next element in a linked list and it requires extra memory for itself.

2) Traversal is difficult

Elements or nodes traversal is difficult in the linked list. As we do in the array, we cannot randomly access any element. If we want to access a node at position n, then we have to traverse all the other elements that come prior to it. That is, if you wish to delete a node somewhere in the middle, you'll have to traverse the list to search for the target value. Hence, it takes a large amount of time to get to a node.

3) Reverse traversing causes memory wastage

It is not possible in a singly linked list to reverse traverse, but it can be done with a doubly-linked list as it comprises the next pointer to the previously connected nodes with each node. There is a wastage of memory due to the extra memory required for the back pointer.

4) Issues with random access

Random access cannot be performed in a linked list due to its dynamic memory allocation factor.

Various types of applications use the linked list as a data structure. It can be used to maintain directory names, perform arithmetic operations in the long integer and manipulate polynomials by storing constants in nodes of the linked list. We can also use it for the functionality of the next and previous images in the image viewer. The linked list allows us to move songs back and forth in the player and makes it easy to implement hash tables. The operating system has a fixed time slot for all the running applications in the computer, and they are stored in a circular linked list.

Hope this article clearly elaborated the advantages and disadvantages of linked lists and also gave you a sneak peek into its amazing applications.

Happy learning!

Shreeya Thakur

Sr. Associate Content Writer at Unstop

I am a biotechnologist-turned-content writer and try to add an element of science in my writings wherever possible. Apart from writing, I like to cook, read and travel.