#### 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
Other Books You May Enjoy
Assessments

# Introducing Map

A few important points to note about Map are:

• It's a data structure that maps keys to values.
• All keys in a Map should be unique. Using duplicate keys for any operation will lead to that operation being implemented on the earlier existing key.
• A key can be mapped to one value. The value can be an object or list of objects.
• Whether we should allow null as a key or not isn't firmly specified. Depending upon our requirements, we can implement a Map that either allows null as a key, or doesn't.
• Since Map doesn't deal with indexes, maintaining the order of the entries isn't guaranteed.
• The objects used as keys in any Map should ideally implement the equals and the hashCode methods. All operations on Map can be done using these methods.
• As keys are used for all operations in Map, we need to be very careful in choosing mutable data types as keys...