Binary tree traversal: Preorder, Inorder, Postorder

See complete series on data structures here:
• Data structures
In this lesson, we have described Preorder, Inorder and Postorder algorithms for binary tree traversal and analyzed their time and space complexities.
See source code here:
gist.github.co...
For more on time complexity analysis:
www.geeksforgee...
For practice problems and more, visit: www.mycodeschoo...
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[@Tommy-yq6vr]

100 times more clearer than those overly complicated computer science books that look like a robot had written them.

[@mohitbv2331]

you are right, he has explained it quite clearly.

[@being1better801]

True

[@FarhanAli-km5id]

🤣🤣🤣

[@joshuasheppard7433]

Spot on .... I'd say 10^9 times clearer.

[@paingoo1370]

I second that

[@FabianLopez_lomba]

I've lost track of how many times this chanel has saved me. Great job!

[@mycodeschool]

Fabian Lopez Thanks a lot :)

[@hafizulhimel3655]

Fabian Lopez add #include header file..ty

[@mohamedeljahmi2454]

I agree. God Bless the instructor.

[@fauzytech]

Agree.

[@prachijha4258]

For me as well

[@pareshb6810]

MycodeSchool: "We are reducing this problem in a self similar manner" Me: "Oh shit! Recursion is coming😭"

[@being1better801]

If you don't understand recursion. Read above sentence again.

[@pareshb6810]

@@being1better801 😂✌️

[@mayankkumar7625]

@@being1better801 😂😂😂😂

[@being1better801]

If you have accepted that recursion is hard for you believe me none of human of this planet will be able to help you understand it. Accept that you are pro in programming. My mantra (Words of Josh Kaufman/The First 20 hours, not mine😅)

[@sudhanwapande2040]

Recursion is easy actually but visualising that recursion is really tough

[@jacquelinelee9836]

One of the most talented tutors I've ever seen on KZbin!!!! You Rock!

[@veritas7010]

The most clear explanations of all youtube, thank you!

[@lukevassor7743]

I think you just saved my M.Sc. exam. You sir are a legend, recursive thank yous with no cap.

[@向前走五十五步]

This is the most elegant explanation of preorder, inorder and postorder. Thank you so much!

[@CSERISHINANDHA]

If you noticed, in every single video where he assumes some random addresses for nodes, the minimum difference between the address of any two nodes will not be lesser than 2x(number of bytes occupied by the node in a 64 byte operating system). Meaning, he always stays alert in what he's doing. Respect+💂

[@divyanshpandit6509]

this man is brilliant! just look at how well he explains these tricky topics in such an intuitive manner

[@arvind617]

Wow...u explained the recursion process really well..way better than other videos on the same topic!!

[@cytriax8657]

I'm studying a Computer Science course in Uni, you clarified within the space of this video and many others what my lecture could not in 3 weeks in relation to data structures. Yay, I think I won't fail my unit now!!! #Hype

[@shivampatel8850]

your visual explanation of recursion function is very influensing and good

[@shahilushah]

Hands down the best channel to learn data structures!!

[@27priancygahlot]

Beautiful explanation.I was stuck for many days in BST.Thanks for saving me out .Great Job guys.Kudos!!

[@siyadhams3047]

hi, in 12:38, I don't find " H " in the BST, hah but great video anyway!

[@sarkarpiu1]

After studying it almost everywhere else around a million times, this video finally helped me understand the pre, post and inorder traversal of trees. Thank you so much for making it so easy to understand. I think every computer science student needs to watch this video.

[@varunVyas]

Thanks a million. videos are precise, consistent teaching method, correctly paced, appropriately supplemented with code/pseudocode, concise. Please do some videos on DP and other algorithms that are asked in competitive contests.string matching, graphs etc. Thanks again man.

[@ThuyNguyen-bu9ge]

I think you made a mistake with In order, there is no H in the binary tree, yet there is one in your list.

[@mycodeschool]

Yeah, That's a mistake. :( I think I have put an annotation to mark the error.

[@vanjavk]

+Tiffastic Nguyen yeah noticed it too :D

[@MohitK96]

+Thuy Nguyen You tried that's why you noticed, it's essential to keep track of every step during recursion in order to learn it.

[@fuzailmohamed8619]

mycodeschool ,while watching it on mobile there are no annotations.

[@venkateshrayala2440]

I figured that

[@rohitdoestech]

Still a useful and brilliant video in 2019

[@rd-cu1vo]

i was a lot confused about the recursion but it made everything clear. thanks a lot!!

[@CSERISHINANDHA]

I don't know if any of you noticed it, at 13:08 , the node for letter 'H' is missing but he wrote it in the result

[@JD-po3uk]

the most thorough video i have seen

[@paz1359]

after 5 years, I found a tutorial who put me out my misery . thank you so much

[@sammyj29]

I have always struggled with recursion but this was such a beautiful explanation! Thank you for making these videos!!

[@sovanmondal2621]

Best Explanation than all other,.....clean and simple.........thank you..

[@bvwalker1]

Nice presentation! Just an FYI, you have the Inorder output listed incorrectly (around 12:35 mark). You added an "H" by mistake making 11 pieces of data instead of 10.

[@sumitkr.3758]

Best collection of lectures for data structure... Thanks a lot👌

[@JamesBrodski]

Amazing video! You're an amazing teacher. Thank you for this.

[@mycodeschool]

Glad it was helpful!

[@sidduroy9150]

@@mycodeschool how are you sir

[@wandererstraining]

Question for anyone who can answer: what would be the use for preorder and postorder traversals? Inorder traversal outputs a sorted list, reverse inorder traversal outputs a reversely sorted list, and breadth traversal gives the correct order in which to draw the tree. So, what are pre and post good for?

[@fsandovc]

I have to say this is one of the most clearer explanation I have found on KZbin, everyone explains the ROOT/LEFT/RIGHT and the code part. But the majority don't explain how the memory is managing the nodes data and how it returns it back. Thanks a lot!

[@SenthilArumugamsp]

Appreciate the effort spend, its really useful for my career.

[@DavidNorman1]

A very helpful and detailed explanation. Thanks for sharing!

[@dheerajdhall8482]

Thank you so much for making these videos. You just made Recursion easy for me. Thank you again(Some Redundancy)

[@md-ayaz]

I owe you a lot brother. You should continue making videos.

[@WebgaraCom]

thanks(){ cout

[@VivekYadav-ds8oz]

Output: ThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksUU]\($^^^!*@{;,

[@VivekYadav-ds8oz]

Output: ThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksUU]\($^^^!*@{;,

[@VivekYadav-ds8oz]

Output: ThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksUU]\($^^^!*@{;,

[@VivekYadav-ds8oz]

Output: ThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksUU]\($^^^!*@{;,

[@VivekYadav-ds8oz]

Output: ThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksThanksUU]\($^^^!*@{;,

[@rbsupercool]

i was waiting for it..finally got it.. every day when i open youtube, first thing i do is check if you have uploaded new videos... thanks a lot.. :)

[@AriffAzman]

nice,thanks, and btw, H doesn't supposed to be there in InOrder, haha still a nice tutorial

[@kiranshettar9323]

+Ariff Azman (opsedar) There is no 'H' in the tree

[@vincent_chow]

+Kiran Shettar look 12:42, which is inorder, there is a slight mistake

[@mafiotu12345]

Thank you a lot man, I really missed those lessons in college and you made me understand them. Bless you :D

[@Lollipop69420]

🙏🙏🙏🙏no words awesome channel no tutorial at local place can't teach better than this pleas go on continuing sir.and btw try to upload videos of java oops concept.

[@priyadharshinis966]

Thanks a lott for making the concept so clear. Great Job😊

[@mdshihabuddin129]

Inorder Tree, Where you found node 'H' ?. The sample tree doesn't contain "H" . Video time : 13.02. It should ABCDEFGIJK.

[@mysteriousyogurt]

Hahah, i guess he forgot to put it in the video. "H" is present at the left link of "I" in a standard BST. Nice observation though.

[@fazleyrabbi8742]

i wanted to ask the same question.

[@fmacoful]

You save my life from Christmas homework. You are the hero. You are hope of humankind!!!

[@saurabhverma6999]

Now my concepts are crystal clear

[@unknownguywholovespizza]

This channel is pure gold 🥇. Everything is just clear without someone showing off instead of teaching. 😀

[@kevin-kuei]

Just wanted to say I really appreciate these algorithm videos. Great explanations, diagraming, and delivery all around. Looking forward to exploring more of your content.

[@kitty-ann5224]

sometimes its hard to follow, because the caption is hiding the writings/images. very good and informative video

[@sudharsan4040]

Great video.Please upload many such videos in future.Thanks.

[@pymondo1147]

Just like that you explained complex stuff.. Hats off to you:):)

[@natureauthor]

Thank you so much! This video was very comprehensive and incredibly helpful. I love that you put so much thought and detail into explaining this concept.

[@parasmani8514]

Great job man. Crystal Clear.

[@Tola-sx3np]

Fantastic video, can we see a link to the space complexity of the binary tree as you suggested it would be in another video?

[@parthokr]

Preorder - 2:30 Inorder - 12:06 Postorder - 12:50

[@heyitsnikhil7956]

give this man a beer!! 🍺

[@thamadaashish2643]

great use of recursion man !

[@dorinbharali7935]

nice tutorial!! Could you plz upload the iterative solution for this BST traversal? It would be of great help. Thanks in advance.

[@poojamohite1106]

Great explanation . Good Job.. Keep it up .

[@VVSDRAWGAME]

I think at 12:36, it shouldn't include H.. But, nevertheless, great video!! Finally understood the concept :)

[@iaktech]

Great Lectures! Thanks a lot.

[@sudheertripathi3882]

while(True) { cout

[@hangchen6131]

Awesome walkthrough of the recursive function of the traversal of a binary tree in detail with a stack structure illustrated! I now fully understand the magic behind the code! Your videos are the best data structure tutorials I can find so far! Thanks :)

[@atonewiththedust]

I think I've finally wrapped my head around recursion thanks to this video. Great explanation!

[@shaileshpachbhai432]

This is very good explanation in simple in lucid language. Great Job :)

[@vivian_who]

This is my favorite subject in university, because of you!

[@vinaybabu_96]

Finally....I found a good one..

[@hectorcarrasco1162]

Great job dude!

[@mudassirshahzadkk]

6 years old but still much better than other latest videos on this topic.

[@adityaojha2701]

Nothing can be better than these playlists.

[@surajupadhyay2200]

very very very good lesson

[@nailarehman7954]

Best Explanation.

[@uchchwasdas2675]

thanks, it's really very helpful.

[@pareshb6810]

MycodeSchool: "We are reducing this problem in a self similar manner" Me: "Oh shit! Recursion is coming😭"

[@joedunder4439]

This is so gloriously helpful. Thank you!

[@lakshmanchoudhary020]

in java:- class BSTNode{ int data; BSTNode left,right; BSTNode(int data){ this.data=data; this.left=null; this.right=null; } } public int preorder(BSTNode root){ if(root==null){ return 0; } else{ System.out.print(root.data+" "); preorder(root.left); preorder(root.right); return root.data; } }

[@lionheart9746]

Thank you for the nice visualization! keep on going this amazing job =)

[@dicksonleung6662]

great video!

[@iamrajagrawal]

You explained so nicely that even a 5th standard student can easily understand this...Thank you so much!

[@mohitvarma1012]

Thanx a lot for all of ur videos !! u really made all this so simple to understand with u r explanation!!!

[@erics4433]

This was very helpful. I was getting a bit confused on how exactly the recursive code was behaving in relation to the tree and your side by side approach really cleared it up for me. Great job, thank you!

[@johns6176]

Awesome video, thank you.

[@bsrafael]

This video is just GREAT. Clear and with all the important concepts about the traversal. Thank you very much for this awesome piece of information :D

[@MoutasemMohammad]

there's no H node at 12:45 in the in-order traversal

[@Crisp3333]

+Moutasem Mohammad That is the same thing I am saying, where did this H come from!

[@FlexerPivot]

you guys are funny

[@AnilGupta-iv1rz]

I would love to see your videos on advanced data structure topic like adjoint set,trie and AVL tree.

[@judemarryshow9834]

For inorder traversal, there is no “H”, it’s “A, B, C, D, E, F, G, I, J, K”.

[@ashutoshmahato723]

can you please add a video about non recursive traversal

[@LATRIBUNEVLV]

Your work is more clear and usefull to me while i try to get my degree than most of my classes and teachers, thx :)

[@kiranranganathan6636]

Hi, there is a small mistake, there is no node H for which you have made reference in IN-Order traversal.

[@SougataDafader89]

Great video!

[@sakshidevi353]

really this video has cleared my all concepts...thanks a lot sir

[@AsifHassanran]

If I declare 'root' as local/global, what should I do in function Insert/ Preorder/ BSTsearch please mention anyone of them at least.

[@viraj_singh]

Inorder answer is wrong, according to example there is no H in the tree but H is mentioned in the example.

[@jsbisht_]

Good choice of colors for the video :)

[@Vampirio20]

This is GOLD !

[@AmgNoWai]

Thank you very much for these wonderful videos they are extremely helpful! Your explanations make these concepts so easy to understand. :D

[@SatnamSingh-sk3hd]

i also understand how recursion work thnks alot man

[@amritpalsingh3089]

sir,please also do explain algorithms too! algorithms are tougher to understand.!

[@kafychannel]

thank you man extremely useful!

[@mehershrishtinigam5449]

I will never forget any of the tree concepts now. Thank you.

[@saquibpandit]

What should be returned if return type is not void and data is NULL int Preorder(Node * root) { if (root->data==NULL) return NULL; // 0 also won't work gives Segmentation fault Preorder(root->left); Preorder(root->right); } Thanks

[@luvon1114]

Absolutely amazing. Thanks for the video. You are a terrfiic teacher. Love your visualization techniques.

[@jimas95]

at the algorithms at C you have written when vertex has not child the programm is going to return NULL , so it will never print their elements so the outpout for inorder will print FDBJGKA