#### 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

# A short introduction to strings

Like dynamic arrays (ArrayList), strings are also represented by a class and have a backup array of characters. Similar to other data structures, strings also can be implemented as mutable and immutable.

Immutable strings in Kotlin are represented by the String class, whereas mutable strings are represented by the StringBuilder class.

The string class doesn't provide any public API to mutate the backed-up character array. So you can only find APIs such as elementAt(), indexOf(), and lastIndexOf() or similar get functions. Though it has mutating APIs such as subSequence(), capitalize(), or similar, they always create a copy of the string and return the updated one without mutating the existing string.

In the other case, StringBuilder offers many mutating APIs such as append(), insert(), replace(), reverse(), and many more. These APIs literally...