#### Overview of this book

Building your own applications is exciting but challenging, especially when tackling complex problems tied to advanced data structures and algorithms. This endeavor demands profound knowledge of the programming language as well as data structures and algorithms – precisely what this book offers to C# developers. Starting with an introduction to algorithms, this book gradually immerses you in the world of arrays, lists, stacks, queues, dictionaries, and sets. Real-world examples, enriched with code snippets and illustrations, provide a practical understanding of these concepts. You’ll also learn how to sort arrays using various algorithms, setting a solid foundation for your programming expertise. As you progress through the book, you’ll venture into more complex data structures – trees and graphs – and discover algorithms for tasks such as determining the shortest path in a graph before advancing to see various algorithms in action, such as solving Sudoku. By the end of the book, you’ll have learned how to use the C# language to build algorithmic components that are not only easy to understand and debug but also seamlessly applicable in various applications, spanning web and mobile platforms.
Chapter 1: Data Types
Free Chapter
Chapter 2: Introduction to Algorithms
Chapter 3: Arrays and Sorting
Chapter 4: Variants of Lists
Chapter 5: Stacks and Queues
Chapter 6: Dictionaries and Sets
Chapter 7: Variants of Trees
Chapter 8: Exploring Graphs
Chapter 9: See in Action
Chapter 10: Conclusion
Index
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# Sets

Another data structure from Chapter 6, Dictionaries and Sets, is a set, which is a collection of distinct objects without duplicated elements and without any particular order. Therefore, you can only get to know whether a given element is in the set or not. The sets are strictly connected with mathematical models and operations, such as union, intersection, subtraction, and symmetric difference.

The exemplary sets, storing data of various types, are shown as follows:

Figure 10.7 – Illustration of sets with integer and string values

While developing applications in the C# language, you can benefit from high-performance set-related operations provided by the `HashSet` class. As an example, you saw how to create a system that handles one-time promotional coupons and allows you to check whether the scanned one was already used. Another example was the reporting service for the system of a SPA center with four swimming pools. By using sets, you...