Swift 3 Fun Algorithms: Recursive Search through Binary Tree

Recursion and implementing a recursive algorithm to perform search is pretty fun once you understand how the algorithm works. In today's lesson we'll go through a very commonly asked interview question of perform a search through a binary tree to find if a value is contained in the set of numbers.

At the very end of the video, we'll compare the efficiencies of this recursive search with a very basic index search that comes out of the box with Swift.

Enjoy.

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[rogerwprice]

What a fabulous step by step explanation and demonstration - THANKS!

[everton_dev]

By far the best channel to learn swift and iOS development. Very well explained concepts, I've learned so much with your videos. Thank you!

[PythonPlusPlus]

I decided to use a switch because it looks nicer. I couldn't decide wether or not to use the guard statement, I decided to just put everything in the switch in the end because it looks neater that way. My attempt at the optimised search function:
func search(node: Node?, searchValue: Int) -> Bool {
switch node?.value {
case nil:
return false
case let value where value! > searchValue:
return search(node: node!.leftChild, searchValue: searchValue)
case let value where value! < searchValue:
return search(node: node!.rightChild, searchValue: searchValue)
default:
return true
}
}

[巴貝里奇]

pretty useful tutorial
and you made the algorithm easy to learn

[young_vz]

Another great video!
I love watching your algorithm vidoes!

[marekchojecki]

Love fridays because of this series :)

[perh]

Hi there, I really like your video but I have an honest question, in your first implementation i.e. before you implement a solution for BST, isn't the complexity of your search O(n)? As your first solution does not appear to care whether or not there is any order, it searches every node from left (first) to right and since 20 is furthest right you should get 6 iterations, which is no better than a linear search on an array. Sorry if I am wrong or mistaken, and I would love for someone to explain why this is not the case.

[CodeWithChris]

Algorithms class from university back to haunt me! haha Great lesson, Brian!

[studentprogrammer]

InterView question: Recursion Definition: is a computer programming technique involving the use of a procedure, subroutine, function, or algorithm that calls itself one or more times until a specified condition is met at which time the rest of each repetition is processed from the last one called to the first: in simple english: its a step by step repetition way of solving programming question using algorithm /class / function etc ultimately getting to a solution..

[SRX]

Great video! It would be cool if you upload more videos like this!

[cesaredecal]

first :3 thank you so much for everything you're doing Brian! I'm currently following your Swift: Firebase 3 course :) will check this recursive search algorithm out!

[kenny_speaks]

seeing list.index(where: {$0 == 20}) was neat! Never used it before, will come in handy! Great video, I've been confused about the binary tree and the Node() class implementation I've seen in Swift examples. This helped a ton! :) thanks

[amirrezaavani]

It was really helpful and now I can feel sweets of codding
Thank you.

[trishalapatne]

Thank you for this great video. You made BST easy now. Please do sorting algorithms and other data structures too.

[doublegdog]

Very well articulated video. Keep up the great work!

[geomichelon]

another greate video...What you think about crossover company ?

[piyushsharma]

thanks for sharing this useful video, hoping to learn more data structures from you.

[developerios]

Something different from twitter series and others, alghoritms are very important IMO... keep it up mate

[timjohnson]

Awesome video Brian! This is helping me prepare for my first live coding interview on Thursday. I wonder if the reason the "(4 times)" is shown when search value is 11 and "(5 times)" is shown with a search value of 20 is because the entire non-nil left side of the tree is searched before the right side. So in the case of searching 11... 5, 1, 14 & 11 nodes are searched.

[jincat]

Great video! Love algorithm lecture from your channel! Wish we could learn more lessons about data structure and algorithm in Swift here! Thank you Brian.