Binary Tree Level Order Traversal | Dataford Interview Questions

Print a binary tree level by level, replacing missing nodes with "*"; leaf nodes are separated by one space and each parent node is positioned relative to its child nodes going upward (rest of the prompt is points-walled).

Asked in the phone screen (coding) stage. Visible part of 1p3a post; remainder hidden behind points wall.

Contract

Implement print_tree(root). root is a nested dictionary with value, left, and right keys, or None; values are single non-whitespace characters. Return a list of strings, one per level. Include "*" for every missing position through the deepest real node, and preserve leading spaces needed for alignment.

Constraints

The tree contains at most 2^8 - 1 nodes.
Each node dictionary contains value, left, and right keys.
Each value is a single non-whitespace character.
Missing children are represented by None.
Return one string for every level from the root through the deepest real node.

Function Signature

def print_tree(root):

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Problem