#### 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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# Rat in a maze

Let’s continue our adventure with examples by solving the rat in a maze problem with a back-tracking algorithm. The diagram is shown as follows:

Figure 9.6 – Illustration of the rat in a maze example

Let’s imagine that a rat is located in the top-left field on the board, which is marked as (0, 0) in the preceding figure, and we need to find a path to the exit, which is located in the bottom-right field and is marked as (7, 7). Of course, some blocks are disabled (shown in gray) and the rat cannot go through them. To reach the target, the rat can go up, down, left, or right only using the available blocks.

You can solve this problem using the recursion to check possible paths leading the rat from the entry to the exit. If the currently calculated path does not reach the exit, you backtrack and try other variants.

The main part of the implementation is the `Go` method, as follows:

```bool Go(int row, int col)
{
...```