Binary Tree Preorder Traversal - LeetCode 144 Python

Explaining Binary Tree Preorder Traversal in Python (Recursive and Iterative!)

Recursion Solution @2:37
Iterative Solution @7:35

Music: Bensound

Lemme know up if you have any questions/comments!:)

[kervinsingh]

1.Beginner friendly tutorial
2.explains step by step what the code does
3. time stamps
Smeshed that like. keep up the good content :D

[gayan]

This channel deserves more subs. Best explanation I found on YT so far.

[mandyzhang]

The recursion solution is fantasic. It is easy to understand and can be used in both inorder and postorder easily.

[kentsang]

I struggled for 2 hours before watching your video. Very clear explaining the steps!!!

[shuhaoliang]

Very clear and intuitive. Thanks for your detailed tutorials and look forward for more good videos!

[davyroger]

Thank you for saving me from coding up a convoluted solution! earned a new subscriber :)

[karineunderwood]

So helpful!! Thank you for sharing this amazing explanation! You rock!

[Rae]

Very clear and simple understanding, really enjoy your video, super helpful! Look forward to seeing more!!!!

[TamNguyen-dksw]

very intuitive and understanable!!! thank you so much!!

[_a-g_]

thank you so much! the codes online without a demonstration really puzzled me like big time. but with your explanation, all is clear!

[mananpatel]

the explanation that you do after writing code is just awesome

[visheshbajpayee]

Please never stop making views. Your way of understanding is really good and your videos are helping me alot in my journey through learning Python

[deeshdeesh]

Thank you so much really clarified a lot of bigger level questions.

keep doing suck amazing work.

Thank you

[rahsoolbeats]

Awesome video! Extremely helpful. Thank you

[divyatalesra]

Amazing explanation!! Thanks so much ma’am!

[RohitMishra-zjoh]

hi Deepti could u please make a video on postorder traversal using both recursive & iterative....

[bruckeundkeinzweck]

hi deepti. you're videos are very helpful for me and i would like to see you getting back to making them soon, they are really helping me get a grasp of BST algorithms.

[shadowhawk]

Hi Deepti, how are you? Thank you so much for your videos! Your explanation is so clear, concise and easy to understand! Learnt a lot😊

[abdo]

Could you please make a video about your career so far, and your thought about ChatGPT and how its going to effect our jobs in the future..

[serenatang]

I am new to coding， can you please explain at 13:00
1. how does the error "Nonetype object has no attribute val" remind you to add the lines there?
2. Why the lines are before you define stack and result?
3. why None?? there's not even a keyword "None" before the line result.append(root.val)?
4. why "is None" instead of "=[]"

Thanks a lot!! sry those are probly stupid and obvious questions, but they are very important to me