Table of contents
1.
Introduction
2.
What is a Linked List?
3.
Why Linked List?
4.
Prerequisites For Linked List
5.
Basic Operations
6.
Standard Questions and Concepts
7.
Types of Linked List
8.
Singly-linked list
9.
Doubly linked list
10.
Circular linked list
11.
Linked List Applications
12.
Frequently Asked Questions
12.1.
What are the applications of linked list?
12.2.
What are the two main types of data structures?
12.3.
What are the advantages of a linked list?
12.4.
What are the different types of linked list?
13.
Conclusion
Last Updated: Dec 23, 2024

How To Master Linked List And Its Importance

Author Mehak Goel
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Introduction

Linked lists are a foundational data structure in computer science, offering a dynamic and flexible way to manage and manipulate data. Unlike arrays, they excel in scenarios where the size of the dataset is unpredictable or frequent insertions and deletions are required. However, understanding and mastering linked lists can seem daunting at first due to their unique structure and pointer-based implementation. In this blog, we will explore linked lists and their structure, types, and common operations.

Linked List

Recommended Topic, Floyds Algorithm and Rabin Karp Algorithm.

What is a Linked List?

A linked list is a linear Data Structure which instead of storing data at contiguous memory locations, stores data at random locations and each node is linked to the other by the use of pointers.

Each node consists of two fields:

  • Data stored at that location.
  • Pointer, which points to the address of the next node.

 

Have you ever thought about why it is called a linked list? Well, the answer is simple as we store data in sequence, i.e in a linked manner in which the address/reference of the next node is stored in the previous pointer.

Also read - merge sort in linked list

Why Linked List?

Some of you might be thinking that we are already having arrays for storing our data then why we need a linked list. Well, there are some limitations of arrays that can be eliminated by using a linked list.

  • Deletion and insertion can be achieved very quickly as they do not require shifting elements while using a linked list.
  • The linked list is dynamic in nature. So, we can change the size according to our requirements.

Prerequisites For Linked List

Before we dive deep into the linked list, we need to have a basic understanding of some topics like:

Basic Operations

Once we have a basic understanding of the Linked list and we know why we need a linked list now it’s time to start learning and coding all basic operations of the linked list. It is crucial to understand and implement the basic operation as these operations are building blocks to master the linked list.

It is very important to have a crystal-clear idea of the linked list structure as many beginners find it difficult because they can’t visualize the linked list. The linked list node consists of two fields: data and another one is the address/reference of the next node.

There are four basic operations on the linked list:

  • Taking input
  • Insertion
  • Searching
  • Deletion

 

Try to implement these operations. While implementing these operations, try to understand each operation’s time and space complexity in depth. Sometimes, you may get direct questions based on time and space complexity in your interviews even at big product-based companies.

Try to implement all these operations iteratively as well as recursively. Once confident in these basic operations try to implement the reverse operation on a linked list, like reversing a linked list and adding two linked lists.

Click here to get a curated list of questions on the linked list.

Standard Questions and Concepts

Now that we have implemented the basic operations and reverse operations on the linked list, now it’s time to dig deeper into the concepts and algorithms related to the linked list. Make sure that you are comfortable with all the basic questions related to the linked list. 

Now the main question is what these product-based companies ask? What should you study to crack interviews at these product-based companies?

Well, here are some standard algorithms and concepts related to the linked list. These techniques and concepts are essential to learning because in some way or the other maximum question related to the linked list are based on these techniques.

One of the techniques that are essential for mastering linked list is:

  • Slow and fast pointers technique. It is a very important technique in the linked list. You should have a good idea and clear logic of how a slow and fast pointer works.

 

To test out your understanding of slow and fast pointers, try to implement these two problems on your own: Finding the middle of the linked list and Detect and remove the loop.

These are some problems that are must to implement for a linked list. These all concepts are so crucial that these questions have been repeatedly asked by Google, Microsoft, Facebook, and Amazon.

Types of Linked List

Till now we talked about the linked list and some essential concepts of the linked list. But there are some variations of the linked list that you should know and have a basic understanding of.

There are three types of linked lists:

Singly-linked list

The singly linked list is the most basic type of linked list. The node of the singly linked list contains data and the pointer of the next node and the last node points to null, which represents the end of the linked list. We can’t move backwards in a singly linked list.

Now we are having a fair bit of knowledge about the singly-linked list and have covered all the basics, you may now try to solve the following problems. These problems are frequently asked in top-notch companies and would help you to ace your technical interviews.

 

Remember knowledge is of no use until put into practice. Practice is very important to ace your interviews. Implement all these problems on your own if you want to master the linked list.

Doubly linked list

A doubly linked list contains a node that has three entries: data, pointer to next node and pointer to the previous node. As we have both previous and next pointer we can move backwards in a doubly-linked list.

Implement the following problem to check your understanding of the doubly linked list:

Circular linked list

A circular linked list is the same as a singly linked list with the only variation that the last(Tail) node of the circular linked list contains the pointer of the first(Head) node.

 

This is not the end of practice. If you feel the need to solve more problems you can find great problems at Coding Ninjas Studio.

It is a great platform developed by some aspiring enthusiasts and working professionals who have experience in companies like Google, Amazon, Microsoft. At Coding Ninjas Studio you get interview problems, interview experiences, and practice problems that can help you to land your dream job.

Linked List Applications

Linked lists have diverse applications across various domains of computer science and real-world programming. Some of the key applications include:

  • Dynamic Memory Allocation: Used in dynamic storage management systems to allocate and deallocate memory efficiently.
  • Implementation of Stacks and Queues: Linked lists serve as the backbone for implementing these linear data structures, providing flexibility in size.
  • Graph Representations: Adjacency lists in graph theory are commonly implemented using linked lists to represent edges efficiently.
  • Polynomial Manipulation: Linked lists are ideal for representing and performing operations on polynomials by storing coefficients and exponents as nodes.
  • File System Management: Operating systems use linked lists for managing file directory structures and memory blocks.
  • Undo and Redo Functionality: Applications like text editors use linked lists to implement undo and redo operations by maintaining a linked history of actions.
  • Real-Time Applications: Useful in systems requiring dynamic data management, such as scheduling tasks in operating systems or maintaining playlists in media players.

Frequently Asked Questions

What are the applications of linked list?

1. Linked list is used to implement Stack and Queues.
2. Linked list is used to implement hashing(open chain hashing).
3. Linked list is used to implement graphs(Adjacency list representation of graphs)

What are the two main types of data structures?

Data structures are of two types:
1. Linear, in which data is stored in sequential order ex. Arrays
2. Non-linear, in which data is stored non-sequentially ex. Trees.

What are the advantages of a linked list?

1. Linked list is dynamic in nature
2. Deletion and insertion are very fast in the linked list.
3. Memory is utilised efficiently in linked lists because we don’t need to declare size in advance.

What are the different types of linked list?

There are three types of linked list:
1. Singly-linked list: We can only move forward in a singly linked list.
2. Doubly-linked list: We can move forward as well as backward in this linked list.
3. Circular linked list: In this linked list the last node contains the address/reference of the first (head) node.

Conclusion

Mastering linked lists is a crucial step in your journey as a programmer or computer scientist. Their flexibility and efficiency in handling dynamic data make them a vital tool in solving a wide range of problems. From understanding their structure to implementing various types and operations, linked lists lay the foundation for more advanced data structures and algorithms.

By exploring their practical applications, you gain insights into how linked lists are used in real-world scenarios, enhancing your problem-solving skills and technical expertise.

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