How To Master Linked List And Its Importance

Table of Contents

Introduction

Linked List is one of the most important topics for technical interviews to crack a job at product-based companies. Questions on the linked list are constantly asked in companies like Google, Facebook, Amazon, and Flipkart.

It’s crucial to have a good grasp of this topic. If you are just a beginner or learning the linked list, then stay with me—I’m about to explain how to learn a linked list from the basic bits to the more complex operations on linked.

Have you guys been wondering how to master Linked List without having to bang your head to the wall or maybe to a bulky textbook?

Let me tell you this, “you have landed on the right page!” Watch this video from one of our experts. You won’t regret it!

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.

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.

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.

Merging two sorted linked list
Print Linked List in reverse order – both using recursion and iteration
Count inversion, a very interesting problem based on enhanced merge sort.
Pair swap
Add 1 to a linked list – List represents a natural number.
Check linked list palindrome

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:

Inserting an element in the doubly linked list.
Deleting an element in the doubly linked list.
Reversing a 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.

Implement the following problems to develop a good grasp on the circular linked list:

Inserting element to the circular linked list
Searching elements in a circular linked list
Deleting a node in a circular linked list

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

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

Frequently Asked Questions

What is a linked list in C++?

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.

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.

Key Takeaways

A basic introduction to the linked list and all standard questions and techniques that you need to practice to master the linked list.
A structured way to learn linked list based on problem-solving to crack jobs at product-based companies.
Practice is the key to master the linked list. Concepts related to the linked list can only be learned by practising.

In this article, we tried to provide you with a way to learn a linked list with all important questions and topics that you should know to master the linked list.

If you feel the need for expert guidance to learn these concepts check out our DSA courses.

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By Pranchal Agrahari