# About the Data Structures and Algorithms in Kotlin category

**URL:** <https://forums.kodeco.com/t/about-the-data-structures-and-algorithms-in-kotlin-category/82113>\
**Category:** Data Structures and Algorithms in Kotlin\
**Created:** [September 18, 2019, 1:20pm UTC](https://forums.kodeco.com/t/about-the-data-structures-and-algorithms-in-kotlin-category/82113 "2019-09-18T13:20:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mandafrederick](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/mandafrederick/32/102369_2.png) [@mandafrederick](https://forums.kodeco.com/u/mandafrederick)\
**Post date:** [September 18, 2019, 1:20pm UTC](https://forums.kodeco.com/t/about-the-data-structures-and-algorithms-in-kotlin-category/82113/1 "2019-09-18T13:20:02Z")

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This is the official forum for our book, Data Structures and Algorithms in Kotlin, available here: [https://store.raywenderlich.com/products/data-structures-and-algorithms-in-kotlin](https://store.raywenderlich.com/products/data-structures-and-algorithms-in-kotlin).

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**Author:** ![hydromac](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/hydromac/32/81494_2.png) [@hydromac](https://forums.kodeco.com/u/hydromac)\
**Post date:** [August 2, 2020, 6:25am UTC](https://forums.kodeco.com/t/about-the-data-structures-and-algorithms-in-kotlin-category/82113/2 "2020-08-02T06:25:52Z")

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Hi @mandafrederick,  
Can You get up link to the source files for the printed book, please ?

The one visible in the book is inactive → [www.raywenderlich.com/store/data-structures-and-algorithms-in-kotlin-sourcecode/Forums](http://www.raywenderlich.com/store/data-structures-and-algorithms-in-kotlin-sourcecode/Forums)

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**Author:** ![avukelic](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/avukelic/32/102689_2.png) [@avukelic](https://forums.kodeco.com/u/avukelic)\
**Post date:** [February 7, 2022, 2:23pm UTC](https://forums.kodeco.com/t/about-the-data-structures-and-algorithms-in-kotlin-category/82113/3 "2022-02-07T14:23:57Z")

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Hello @mandafrederick

I was going through this book and I think I have found one mistake in the Deserialization section of the Binary Tree chapter.

[https://www.raywenderlich.com/books/data-structures-algorithms-in-kotlin/v1.0/chapters/7-binary-trees](https://www.raywenderlich.com/books/data-structures-algorithms-in-kotlin/v1.0/chapters/7-binary-trees)

In the first code snippet, it says

```auto
fun deserialize(list: MutableList<T?>): BinaryNode<T?>? {
  // 1
  val rootValue = list.removeAt(list.size - 1) ?: return null

```

Seems like this `rootValue should be list.removeAt(0) ?: return` null because after this instructions said ` In the other deserialize function, find the removeAt(0) call and change it to list.removeAt(list.size - 1):`

And thanks to the authors for this awesome book, I’ve been going through it the last few days and everything is crystal clear! Good job.