#### 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

# Maps – working with key-value pairs

The Map interface is a bit different than all the other interfaces in the collections framework, such as Set or List. Unlike them, it works with key-value pairs. If you're thinking of Pair, then let me say no, this is not similar to Pair. A Pair is just a pair of two values combined together while a Map is a collection of key-value pairs.

In a Map, keys are unique and cannot be duplicated, whereas values can be redundant. If you try to add two values with the same key, then the latter one will replace the previous one. Values, on the other hand, can be redundant/duplicate. The main reason behind this behavior is that in Map, items are not stored based on order or anything else, but rather a value is stored and retrieved with respect to its key, so redundant keys will make it impossible to distinguish them from each other and to...