#### Overview of this book

Data structures and algorithms are more than just theoretical concepts. They help you become familiar with computational methods for solving problems and writing logical code. Equipped with this knowledge, you can write efficient programs that run faster and use less memory. Hands-On Data Structures and Algorithms with Kotlin book starts with the basics of algorithms and data structures, helping you get to grips with the fundamentals and measure complexity. You'll then move on to exploring the basics of functional programming while getting used to thinking recursively. Packed with plenty of examples along the way, this book will help you grasp each concept easily. In addition to this, you'll get a clear understanding of how the data structures in Kotlin's collection framework work internally. By the end of this book, you will be able to apply the theory of data structures and algorithms to work out real-world problems.
Table of Contents (16 chapters)
Preface
Free Chapter
Section 1: Getting Started with Data Structures
A Walk Through - Data Structures and Algorithms
Arrays - First Step to Grouping Data
Section 2: Efficient Grouping of Data with Various Data Structures
Introducing Linked Lists
Understanding Stacks and Queues
Maps - Working with Key-Value Pairs
Section 3: Algorithms and Efficiency
Deep-Dive into Searching Algorithms
Understanding Sorting Algorithms
Section 4: Modern and Advanced Data Structures
Collections and Data Operations in Kotlin
Introduction to Functional Programming
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Assessments

# Understanding the Doubly Linked List

In many operations operated on a Singly Linked List, we've observed that, to get a previous node of any particular node, we need to traverse from the head of the LinkedList. This is a performance hit. Of course, we can ignore it if the LinkedList is small but, for Linked Lists that are big in size, the time taken to get the previous node is larger. To avoid this performance problem, we can simply store the previous node reference of every node in the same way we store the next node reference. This is what we call a Doubly Linked List.

We can represent it in a graphical way as follows:

Like a Singly Linked List, we can perform all of those operations in a Doubly Linked List too. Moreover, all of those operations can be performed much faster because of the previous node's storage. Let's see the full implementation of a Doubly...