#### 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.
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
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

# Implementing ArrayMap

In the previous section, we have seen how to implement HashMap. Though it is one of the best data structures for key-value pairs, we still can learn other similar data structures that have slightly different approaches to achieving the same goal. ArrayMap is one of them. Before we go ahead with the implementation of ArrayMap, let's first understand the difference between this and HashMap to understand why we even need ArrayMap and where can we use it:

• HashMap uses Nodes to store key-value pairs. So, in addition to the actual data, it also allocates memory for the reference to the next node, whereas ArrayMap doesn't need this.
• To avoid hash collisions, HashMap creates a larger array even though most of the indexes could be empty, whereas ArrayMap doesn't require this.

We'll understand more about the aforementioned points in later parts...