AVL Trees & Rotations (Self-Balancing Binary Search Trees)

[@TheAntloo]

Hey man just realized I never actually thanked you, I passed my interview and your videos were so much help!!! You are awesome!

[@BackToBackSWE]

great - flourish in life friend

[@DavidVCastro]

@TheAntloo, how many times have you used an AVL Tree in your job of two years? 🙂

[@stealth7854]

@@DavidVCastro lmao

[@yonathanmichael1910]

This kid's older brother is one of my little homies from college. Now i'm reviewing algorithms and the little little homie is teaching me. Both impressive young men who are making their families proud.

[@BackToBackSWE]

haha hey

[@WyMustIGo]

Looks like this homie stopped the videos because there is no money in teaching for free. That means he gained wisdom and is using his knowledge to make a profit instead... Homie is getting wise.

[@dramallama111]

As always, why is that some guy on youtube can explain these concepts so much better, and in a shorter amount of time than most college professors? It boggles the mind.

[@BackToBackSWE]

Check out the free DSA Mini-Course 👉backtobackswe.com/five-day Table of Contents: Introduction 0:00 - 2:07 Tree Height 2:07 - 3:51 Node Balance 3:51 - 4:21 Balance Calculation Practice 4:21 - 7:32 Breaking The AVL Property 7:32 - 8:32 Rotations 8:32 - 12:52 Right Rotation 12:52 - 15:58 Left-Right Rotation 15:58 - 18:12 Left Rotation 18:12 - 18:50 Right-Left Rotation 18:50 - 19:44 Support Us At backtobackswe.com 19:44 - 20:37 Errors: 0:19 - 1:41 The is not a BST, this is fixed at 1:41. 11:08 NIT: The purple triangle is > y (strictly greater) and > x I hope this helps someone. If there are any mistakes let me know and I'll update the "Errors" section.

[@Delinester]

This author explained AVL trees better than our professor in 2 lectures. Thank you!

[@BackToBackSWE]

Happy Holidays 🎉 Thank you for your kind words, Delinester! We'd love to offer you a 40% Off our exclusive lifetime membership just use the code CHEER40 - backtobackswe.com/checkout?plan=lifetime-legacy&discount_code=CHEER40

[@OktayDerman]

professors are like not-teaching teachers at schools stay away from them, go after assistants.

[@BoonkiCoC14]

Before i watch the video again gotta let you know, this was hands down the best illustration ideo for AVL trees. The illustrations are easy to follow. Cheers.

[@MaxPicAxe]

OMG the way you explained it around 12:30 makes so much sense. I don't need to memorize anything, I just need to think through whether each triangle is less than or greater than x, and the same thing for y, and then it's so easy to perform the rotation. Thank you!

[@BackToBackSWE]

Thank You, Glad you liked it. Do check out backtobackswe.com/platform/content and please recommend us to your family and friends :)

[@hawadoh]

After spending 12 hours non-stop trying to fix just one bug in my AVL tree (with parent node pointers) I've decided to take a step back and watch this video, and this is so much help! I am going to try again now after eating

[@arjunkashyap8896]

This is the clearest explanation I have seen on Balanced Trees so far. I was trying to learn this topic back in march and I could not find a good resource to understand and I dropped this topic. Now today I picked it back up and I found your video. Thank you so much !! ---> Subscribed

[@BackToBackSWE]

sure!!

[@rustyshackleford2605]

The clarity of your explanation is astounding. Thanks a bunch!

[@BackToBackSWE]

Haha! thanks. Try out the free mini course on our website - backtobackswe.com/

[@Happy.Vagabond]

Hey you probably get this a lot, but you helped me so much to prepare for my interview. I have been non-stop preparing for my coding interview at my dream company at Microsoft. I've been prepping 8-10 hours a day every single day on LeetCode and watching your videos. You have helped me so much in learning the fundamentals and learning how to approach different coding problems. I'm glad to say that I did get an offer from Microsoft yesterday! Again, I thank you so much. Your videos were the main reason I was able to get this offer. You have truly changed my life.

[@BackToBackSWE]

great to hear. grow strong.

[@S189-g7s]

hey! im new in coding, can you explain me how did you prepare and any advices for beginers like me? i would appreciate a lot!

[@hascuhas]

Thank you, I never understood AVL trees from my university courses. Your explinations made it crystal clear for me.

[@יעלליפשיץ-ס6ש]

Thank you for this video! finally I understood AVL trees!! I will keep commenting each video I see that helped me to keep supporting you! you are great!

[@BackToBackSWE]

great

[@abhinavsingh4221]

Just few moments ago I was really missing you and your content and now your video is here!! Welcome back buddy :)

[@BackToBackSWE]

hey.

[@amirPenton]

Started BSTs in class and we have to implement our own AVL tree. The textbook didn't cover left-right or right-left rotations nearly as well as you did. Thanks so much for this video, I will be citing this in my project.

[@BackToBackSWE]

sure

[@doublaitmaxim7540]

I have a test tomorrow on binary trees and this video really helped me out so thank you so much! !!

[@BackToBackSWE]

great

[@hyeonsooleesandoz998]

Perfect explanation of AVL rotation !! I've watched the videos about this subjet in French, Korean and English. And only your video makes me understand CLEARLY and PERFECTLY. Thank you so much.

[@BackToBackSWE]

Glad it helped 😄 We also have a Free 5 Day DSA Interview Prep Mini-Course - backtobackswe.com/ 🎉

[@sickmilk]

First time here. Was searching info about AVL, had problems with understandings it. And occasionally find this channel. Man it is incredible. Totally awesome. It's so clear for me after your explanation. I've also checked the list of your videos. And I am joining this great channel and will advise it to my friends! Thanks for the content!

[@BackToBackSWE]

thanks and great to hear

[@lalitvavdara5841]

This Is the crystal clear explaination of AVL trees I have seen on the Internet....!! You are awsome!!

[@BackToBackSWE]

sure yo

[@lalitvavdara5841]

@@BackToBackSWE stackoverflow.com/questions/63649722/satisfying-properties-of-nodes-after-rotation-in-avl-trees I have this question after watching your video It would be really helpfull if you can answer it or any one reading this could answer.

[@weallgotwoodandnails]

Clear, concise, and invaluable. Thank you for uploading this.

[@BackToBackSWE]

thanks - sure

[@yoyocontact5181]

I lost my job due to the covid-19, now learning and prepping for Tech interviews. Life is tough these days. Also, please please upload more videos on Linkedlists . ( all if possible - from start to end )

[@BackToBackSWE]

message us we can work something out - backtobackswe.com/contact

[@yoyocontact5181]

@@BackToBackSWE Done. Please check.

[@jonathantraverso4072]

You have a gift when it comes to explaining things!

[@MoscleBrog]

my god i understood his explaination and i feel fun doing this work it kinda feel like rubiks cube. this channel is a magic of understanding

[@stevendeng2758]

It's definitely the best course that I've ever seen about AVL tree.

[@BackToBackSWE]

thanks

[@shilpag08]

I actually like you being on the frame. Helps to focus more and real lecture feeling

[@BackToBackSWE]

nice

[@eishkapoor703]

Hey man, don't comment alot but I just wanna thank you for being a big part in me getting an internship. The work you do is invaluable, and I for one really appreciate it. Keep grinding these out, you got a life long sub in me

[@nands4410]

Congratulations Where did you get the internship at

[@yutaitadori7318]

Yeah eger to know @Eish

[@BackToBackSWE]

Congrats mate! Keep hustling

[@timjoyalle318]

I found your channel smack in the middle of my data structures and algorithms class. We just started covering this. Excellent!

[@BackToBackSWE]

That is awesome!

[@raywei1701]

OMG SO CLEAR sooooo clear guys watch it , this is the best video for understanding the AVL tree~!

[@BackToBackSWE]

Happy Holidays 🎉 No, you are the best Raywei! We'd love to offer you a 40% Off our exclusive lifetime membership just use the code CHEER40 - backtobackswe.com/checkout?plan=lifetime-legacy&discount_code=CHEER40

[@DanielDiaz-rq3ko]

I know this video came out awhile back but if you see this, thank you so much! I just didn't understand it in class and when my professor explained it again to me. You literally made this such an easy concept to get!! Thank you !!!!

[@BackToBackSWE]

Glad it helped!

[@benzeltser9851]

NEVER STOP UPLOADING

[@BackToBackSWE]

OK I WON'T

[@pokepe12]

Thanks a lot man, my professor's explanation was needlessly complicated so this helped a lot.

[@binupandey6247]

Hi 👋

[@BackToBackSWE]

Haha! why don't you explore our free mini course - backtobackswe.com/

[@elijahye7049]

Around 11:25, when the purple tree has to be greater than y right? Since y < x and purple >= x.

[@bradhanks7837]

I'm just commenting to help your videos rank. :) Great stuff and I appreciate all the time you have invested in this channel.

[@BackToBackSWE]

haha tru and yeah jeez its been a year, almost 2

[@akshayagarwal2714]

Benyam, you are PRO man! I am fan of your teaching style! Your videos have helped me a lot in my prep. Now I have come back for yet another interview, going though your videos first for a quick learning. May this channel be in everyone's recommendation! KZbin you better be listening! XD

[@BackToBackSWE]

thanks - we are humbled

[@mattrieckenberg]

Thank you. You explained it much better than my professor

[@BackToBackSWE]

thanks

[@cashdrawing_danlee]

Great video! I understand in just 20 mins which i can not do that in other video

[@mayurkoli4145]

Hey hey!!! My friend is back, Welcome ✌️✌️☺️☺️

[@BackToBackSWE]

hey.

[@itskingshon]

Your tutorials save me every time!

[@BackToBackSWE]

Thank You, Glad you liked it. Do check out backtobackswe.com/platform/content and please recommend us to your family and friends :)

[@adarshsharmanit356]

Welcome Back Brother ...Love from INDIA

[@BackToBackSWE]

love from 'MURICA 🚜🌽

[@adarshsharmanit356]

@@BackToBackSWE Learnt new word "MURICA" LoL

[@BackToBackSWE]

@@adarshsharmanit356 nice

[@WatchM3Fail]

This is the simplest vid I’ve seen on this, thanks!

[@BackToBackSWE]

Glad you liked it!

[@shilpag08]

Hey buddy, you are amazing. Surprisingly I could end up with a solution to a Salesforce coding interview. All with the method of thinking and approach that you convey.. I dont think I would ever get the crux with any other site. Thanks a lot . Please keep posting videos , would love to hear you

[@BackToBackSWE]

Amaze. Keep grinding!

[@badrivenkatesan6045]

I've never waited eagerly for the next video of any of the youtube channels literally except yours. Every syllable of your explanation makes sense and is very clear. I wanted to request video for few leetcode problems, try to include these in your line-up. Dungeon Game, Path Sum III, Frog Jump. Thanks in advance!

[@BackToBackSWE]

thanks! but we likely wont be able to do those. We have a lot of organizational things going on that have us busy

[@manhalrahman5785]

Thanks I used to hate avl trees a lot because of rotations. But this video fixed it

[@BackToBackSWE]

great.

[@jenweatherwax7113]

Lost me when counting nodes became positive and negative @6:10 ...is it negative when you go right, and positive if left?

[@BackToBackSWE]

Hi, is this referring to balance at a node?

[@jenweatherwax7113]

Back To Back SWE Yes 😂 that is very confusing for me. All the positive 1 and negative 1 values

[@JessPen00]

my professor literally puts me to sleep, thank you so much for this video

[@BackToBackSWE]

Haha! explore our full DSA based courses with promo code ‘KZbin40’ with a 40% discount - backtobackswe.com/pricing

[@farhan787]

Most awaited video, thanks Benyam ❤❤

[@BackToBackSWE]

sure.

[@mritunjaypathak251]

Dude Where are you these days, no video for 8 months........you ok buddy?

[@ishaansrivastav5732]

Its hard to find a teacher who explains better than you SWE. Also, +1 on the tries tutorials would love that

[@BackToBackSWE]

thanks and ok

[@kirillzlobin7135]

12:45 How did we fix the balance if the tree became heavy on the other side

[@0x1h0b]

thank god !!.. finally you are back.. good to see you buddy

[@BackToBackSWE]

hey.

[@KanekiSidibe]

This tutorial is awesome, since there is no dislike button, I just let you know in advance !

[@mystica7284]

yo welcome back!!! thanks for helping us. ;)

[@BackToBackSWE]

sure.

[@eberrodrigues4531]

Clear yet thorough. Thank you man!

[@BackToBackSWE]

Sure!

[@cocoarecords]

The legend is back with a new video

[@BackToBackSWE]

I am normal.

[@jkim5118]

Welcome back, Ben!

[@BackToBackSWE]

hey.

[@jkim5118]

@@BackToBackSWE Yo Ben, is the discussion section on BTB SWE still active? I've posted some questions on this video.

[@gcraneorigami]

Absolutely stellar explanation

[@BackToBackSWE]

thx

[@QwertyNPC]

For 15:10 the nodes You drew and erased I think the point is they can't exist, or rather if they existed the tree would be actually balanced. Or am I missing something ?

[@BackToBackSWE]

I'm not sure what I said (rapid replying to comments can't go in and watch and I don't like watching myself)

[@svenzanetti5637]

Very clear explanation! Is the tree at 8:30 actually a BST though? Because 0 is to the right of 2...

[@BackToBackSWE]

I think I correct it

[@thatoneguy9287]

Thank you, it definitely helped alot but still i cant figure how do i determine if i need a left or a right left rotation? Like on what do i have to look to know which to use?

[@kllau719]

This video really helped me to understand AVL tree! thanksssss :)

[@BackToBackSWE]

Great!

[@shine0nme135]

absolutely loved the way you explain the concept here thanks a lot this really helps me

[@manojrajasekar6035]

Yayy ! Welcome BACK Ben !

[@BackToBackSWE]

hey.

[@prohunter191111]

Your explanation was very clear, thank you very much you helped me a lot

[@IStMl]

finally a natural explanation

[@marcocaniglia2047]

awesome video, my professor should watch these before lecturing lmao. Thank you!

[@BackToBackSWE]

lol thanks!

[@satheshbm92]

Look who's back :) Great as usual Ben

[@BackToBackSWE]

hey.

[@pietasharp]

what is high of tree when on right side i see 2 nodes and left 2 nodes plus 1 note on the top? H(Tr)+1=2+1=3?

[@chrispy808]

Best explanation of this thank you!

[@moosegoose1282]

i exited out my prof zoom lecture to watch this. thank u

[@BackToBackSWE]

haha! try our free mini course to explore more cool stuff - backtobackswe.com/

[@marc-y5e]

I have a really important interview tomorrow. If I remember I’ll come here and update.

[@sexcommunist]

Hey, how was your interview?

[@sameerplaynicals8790]

11:20 the purple node can't be equal to y, because the insertion condition was, smaller=left, bigger or equal to=right.

[@manhalrahman5785]

Yay Back to back is back

[@BackToBackSWE]

hey.

[@j_blue6784]

Thanks, you explained it better than my prof! xD

[@Andrypka]

Great video! You're a great teacher. Keep it up!

[@BackToBackSWE]

Thank you, glad you liked it 😀 Do check out backtobackswe.com/platform/content and please recommend us to your family and friends 😀

[@BurahaunUddin]

Great video. Quick question though: Typically to calculate balance factor should we not do height of right - height of left. This way if its a left heavy tree you can tell because the balance factor will be < -1 and a right heavy tree will have a balance factor > 1?

[@brainwizard8915]

Wow what a sleek explanation

[@BackToBackSWE]

haha

[@ege6142]

best dude ever. Thank you man

[@VinoryreGali]

Thank you very much, your video helps me a lot, handsome MAN

[@joshreynolds4164]

he's back!

[@BackToBackSWE]

hey. I never left, just been working on backtobackswe.com.

[@Rishirajsingh2758]

Hey bro , I have loved your teaching methodology , I have started visualising the algorithms , I love you man thank you so much. Could you try to cover up segment trees if possible

[@BackToBackSWE]

great. and yes.

[@patrickneff7846]

Great explanation. Very clear, thanks.

[@BackToBackSWE]

thanks, glad it helped! There are other codes at - backtobackswe.com/ check it out. Would love some feedback

[@gaasong2615]

Thank you so much for the best explanation I ever had.

[@BackToBackSWE]

Amaze! do try our free mini course - backtobackswe.com/

[@omitHD]

8:00 From what I understood previously, the first node is "0", then going down from there, whether left or right, it is increased by one. Why does he only start "0" at the second nodes instead of the first one?

[@123cheezecakehd]

I think it's just to make the mathematical formula work, but yeah it's confusing.

[@hanieyoosefi2169]

Hi I just can say thank you so much.your video was a great help to me:)

[@BackToBackSWE]

Glad to hear that :) Check out the free mini course on the website - backtobackswe.com/

[@supamdeepbains5172]

King's BACK!

[@BackToBackSWE]

I am normal, a civilian

[@youngsinatra1]

awesome video and explanations!

[@kevinw6237]

thank you very much sir. very nice explanation indeed. is there a subsequent video that demonstrate code examples?

[@XultrashaviT]

This is amazing. thank you so so much, now i know how to do rotations

[@ahmedsidi3976]

Thank you thos videos are extremely helpful ! Keep going you're the best

[@BackToBackSWE]

haha! thanks. Give a shot to the free mini course on the website - backtobackswe.com/

[@HoTuMinuet]

holly crap your explanation is spot on! thanks a lot

[@chudchadanstud]

Could you not flatten the tree, get the node with the value closest to the median and set it as the root?

[@TrueDetectivePikachu]

right in 6:09 I decided to just pause and get to code to see if I can understand it. I ended up with something not very stable but it works XD Done in Python, I'm not sure if this may be O(n log n), it prolly depends on how bad the tree that is traversing is class Node(object): def __init__(self, data=None): self.data: object = data self.left: Node = None self.right: Node = None def get_height(b: Node): def inner(b: Node): if b is None: return -1 return max(inner(b.left), inner(b.right)) + 1 return abs(inner(b.left) - inner(b.right))

[@TrueDetectivePikachu]

still figuring out how to implement the rotation btw, ended in either a stack overflow or loosing a bunch of nodes along the way

[@ghostfjdgcsusvsgsj]

Thanks for the great explanation

[@AparnaBushan]

Thank you for this amazing video!

[@justinkim3133]

thanks a lot this video helped me understand avl trees!

[@BackToBackSWE]

Thank You, Glad you liked it. Do check out backtobackswe.com/platform/content and please recommend us to your family and friends :)

[@Wolverine_261]

Can't find C++ programs for AVL on your website

[@juliax3881]

love your video! so clear! thanks.

[@BackToBackSWE]

sure!

[@a_k__]

Which app on iPad r u using for demonstration? Seems handy

[@abugslife2461]

THANK YOU SO MUCH FOR THIS VIDEO!! Very well explained and clear :) Helped me a lot!!!

[@recoverybot777]

amazingly explained