Community

Ask A Question
Filters
By Category
Notifications
Subscribe You’re not receiving notifications from this thread.

Binary Tree Inorder Traversal (Main Thread)

Here is the interview question prompt, presented for reference.

Can you write a function to traverse a binary tree in-order, and print out the value of each node as it passes?

js 4 \ 5 / 6

The example would output [4, 6, 5] since there is no left child for 4, and 6 is visited in-order before 5.

The definition of a tree node is as follows:

js function Node(val) { this.val = val; this.left = null; this.right = null; }

Follow up: you'll likely get the recursive solution first, could you do it iteratively?

You can see the full challenge with visuals at this link.

Challenges • Asked over 1 year ago by Jake from AlgoDaily

Jake from AlgoDaily Commented on Jul 09, 2019:

This is the main discussion thread generated for Binary Tree Inorder Traversal.

Jake from AlgoDaily Commented on Jul 09, 2019:

Hey @mattvanwinkle:disqus, I went through and double checked all of the tests for tree questions. They should be fine now after a hard refresh and clicking "RESET".

Thanks for being on top of this!

Anonymous Commented on Apr 05, 2020:

I think the BST shown is incorrect.
```
4
\
5
/
6

This tree violates the condition that a left child should be less than its parent. I think the tree should look like this:

4
\
6
/
5
``
Then the in order traversal woud be:[4, 5, 6]`

Anonymous Commented on Aug 06, 2020:

The Python skeleton code, line 3 should be "self.val = v" rather than "self.v = v"

Jake from AlgoDaily Commented on Aug 06, 2020:

I believe you're referring to the first Python community solution. That was a new Node class defined by one of our users, and it works because it's self-defined and doesn't rely on our definition.

Jake from AlgoDaily Commented on Aug 06, 2020:

This problem is for any binary tree, not necessarily just binary search trees.

Anonymous Commented on Aug 12, 2020:

Shouldn't the Postorder traversal be left-right-root? Currently, it shows the same ordering as In-Order.

Jake from AlgoDaily Commented on Aug 24, 2020:

Thank you! Fixed.