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? 🙂

[@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.

[@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!

[@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.

[@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

[@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 :)

[@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/

[@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

[@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/ 🎉

[@doublaitmaxim7540]

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

[@BackToBackSWE]

great

[@hascuhas]

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

[@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.

[@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.

[@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!!

[@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

[@frankhu5418]

I got a Microsoft SWE II position from your awesome videos! Thank you so much for your videos, I really don't think I would have been able to do it without you.

[@BackToBackSWE]

great to hear. mission accomplished. May we get a testiomonial from you? You can message Ben at www.linkedin.com/in/bephrem and we can go from there. If not all is well, congratulations.

[@frankhu5418]

@@BackToBackSWE I sent an invite from my LinkedIn with a msg. Not sure how you want to do the testimonial pending your response.

[@shilpag08]

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

[@BackToBackSWE]

nice

[@stevendeng2758]

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

[@BackToBackSWE]

thanks

[@weallgotwoodandnails]

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

[@BackToBackSWE]

thanks - sure

[@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

[@benzeltser9851]

NEVER STOP UPLOADING

[@BackToBackSWE]

OK I WON'T

[@jonathantraverso4072]

You have a gift when it comes to explaining things!

[@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!

[@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

[@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

[@abhinavsingh4221]

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

[@BackToBackSWE]

hey.

[@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!

[@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

[@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

[@mattrieckenberg]

Thank you. You explained it much better than my professor

[@BackToBackSWE]

thanks

[@manhalrahman5785]

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

[@BackToBackSWE]

great.

[@WatchM3Fail]

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

[@BackToBackSWE]

Glad you liked it!

[@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/

[@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

[@eberrodrigues4531]

Clear yet thorough. Thank you man!

[@BackToBackSWE]

Sure!

[@farhan787]

Most awaited video, thanks Benyam ❤❤

[@BackToBackSWE]

sure.

[@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?

[@cashdrawing3264]

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

[@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 :)

[@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!

[@mayurkoli4145]

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

[@BackToBackSWE]

hey.

[@adarshsharmanit356]

Welcome Back Brother ...Love from INDIA

[@BackToBackSWE]

love from 'MURICA 🚜🌽

[@adarshsharmanit356]

@@BackToBackSWE Learnt new word "MURICA" LoL

[@BackToBackSWE]

@@adarshsharmanit356 nice

[@IStMl]

finally a natural explanation

[@mritunjaypathak251]

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

[@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

[@cocoarecords]

The legend is back with a new video

[@BackToBackSWE]

I am normal.

[@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

[@gcraneorigami]

Absolutely stellar explanation

[@BackToBackSWE]

thx

[@JessPen00]

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

[@BackToBackSWE]

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[@0x1h0b]

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

[@BackToBackSWE]

hey.

[@kevinw6237]

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

[@marc-y5e]

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

[@sexcommunist]

Hey, how was your interview?

[@chrispy808]

Best explanation of this thank you!

[@prohunter191111]

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

[@KanekiSidibe]

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

[@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

[@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.

[@youareunderarrest.3173]

I kind of miss him shouting near that white board. Welcome back. ✌️

[@BackToBackSWE]

hey.

[@shine0nme135]

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

[@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

[@Yoavlevavi]

This video saved me 40 min before my test. T

[@Yoavlevavi]

thanks!!

[@ege6142]

best dude ever. Thank you man

[@brainwizard8915]

Wow what a sleek explanation

[@BackToBackSWE]

haha

[@gaasong2615]

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

[@BackToBackSWE]

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

[@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/

[@recoverybot777]

amazingly explained

[@リンゴ酢-b8g]

A balanced binary tree, also referred to as a height-balanced binary tree, is defined as a binary tree in which the height of the left and right subtree of any node differ by no more than 1.

[@joshreynolds4164]

he's back!

[@BackToBackSWE]

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

[@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

[@manhalrahman5785]

Yay Back to back is back

[@BackToBackSWE]

hey.

[@manojrajasekar6035]

Yayy ! Welcome BACK Ben !

[@BackToBackSWE]

hey.

[@kllau719]

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

[@BackToBackSWE]

Great!

[@j_blue6784]

Thanks, you explained it better than my prof! xD

[@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.

[@mystica7284]

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

[@BackToBackSWE]

sure.

[@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?

[@naman74856]

Your videos are awesome...Please launch a competitive programming course..💁

[@BackToBackSWE]

thanks and I personally can't

[@elijahye7049]

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

[@ghostfjdgcsusvsgsj]

Thanks for the great explanation

[@marcocaniglia2047]

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

[@BackToBackSWE]

lol thanks!

[@a_k__]

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

[@youngsinatra1]

awesome video and explanations!

[@WrongNicholas]

helping me through data structures

[@BackToBackSWE]

Happy Holidays 🎉 Thank you for your kind words, Wrongnicholas! 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

[@XultrashaviT]

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

[@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 😀

[@vamsishankar2825]

What is the gear you use for making these videos? Like the quality is excellent.

[@BackToBackSWE]

I think I addressed in a different comment, but not fully sure now I forgot. iPad...mic cover...some $50 mic off amazon (Samson QC50? not sure)

[@vamsishankar2825]

@@BackToBackSWE oh.. ok thanks.

[@AlWwW1]

Hey! I’m also a UMD student, great video! I was wondering what camera do you use to record and what mic do you use? Thank you

[@BackToBackSWE]

hey. Camera: www.amazon.com/Canon-Mirrorless-Camera-EF-M15-45mm-Video/dp/B079Y45KTJ Mic + Mount: www.amazon.com/gp/product/B07K1XSDZP/ref=ppx_yo_dt_b_asin_title_o04_s00 iPad: www.amazon.com/gp/product/B07XL7G4H6/ref=ppx_yo_dt_b_asin_title_o02_s00 Pencil: www.amazon.com/gp/product/B082V9VFFZ/ref=ppx_yo_dt_b_asin_title_o02_s01

[@supamdeepbains5172]

King's BACK!

[@BackToBackSWE]

I am normal, a civilian

[@reine2472]

this is the best explanation

[@BackToBackSWE]

thanks

[@AparnaBushan]

Thank you for this amazing video!

[@bennyjoo82]

You are a legend.

[@BackToBackSWE]

thx

[@satheshbm92]

Look who's back :) Great as usual Ben

[@BackToBackSWE]

hey.

[@arrahul316]

Thanks bro....this is a great content. It will be useful if we have an example where we have say 5 or greater number of nodes and left or right right heavy with left->right or right->left rotation explained. Again, many thanks for this content. You just rock.. Another suggestion is whether we could explain some practical applications of each DS/Alg as and when you cover them in each video. Like now I know what is AVL tree's properties-> Self balancing. Now where is this Self balancing mandatory in some real world problems. Yes we could google this out or get from intuition. But it will be good conclusion to any video you present, once you have this explained. Again, just a thought. Not an absolute requirement. Thanks Bro. Have a good one!

[@BackToBackSWE]

sure - ok, and u too

[@juliax3881]

love your video! so clear! thanks.

[@BackToBackSWE]

sure!

[@meloth01]

short and precise thank you

[@HoTuMinuet]

holly crap your explanation is spot on! thanks a lot

[@maxjohnson7623]

Thank you, great explanation!

[@BackToBackSWE]

Glad it helped. We'd love for you to check out our Free 5 Day DSA Interview Prep Mini-Course - backtobackswe.com/ 🎉