45 minutes phone interview: I was asked to right the code and explain the logic. No need to execute anything.
Q - Challenging Project you worked on and specify the technical challenges how you resolved it. (10 mins)
Q - To decrypt a message you need to travel left-most to the right node in a tree. For given input find the decoded string. (~30 mins)

(last 2 mins) : Ask questions to interviewer.

Tried to suggest various approches :

• Something on the lines of Inorder traversal
• create skewed tree
  Got nervous as the time passed and couldn't come up with a convincing solution. Pretty disappointed.

Traversal :

Or similar to : https://leetcode.com/problems/binary-tree-vertical-order-traversal/