Given the following memoization cache after computing maxDepth on a binary tree: memo = {nodeA: 3, nodeB: 2, nodeC: 1} If nodeA is the root, nodeB is its left child, and nodeC is nodeB's left child, what is the maximum depth of the tree?

hard🔄 Reverse Engineer Q9 of Q15

Tree: Depth-First Search - Maximum Depth of Binary Tree

Step-by-Step Solution

Solution:

Step 1: Interpret memo values
memo[nodeA] = 3 means max depth from nodeA is 3.
Step 2: Confirm root depth
Since nodeA is root, max depth of tree is 3.
Final Answer:
Option D -> Option D
Quick Check:
Root's memo value gives tree max depth [OK]

Quick Trick: Root memo value = max depth [OK]

Common Mistakes:

MISTAKES

Picking child node depth
Adding memo values incorrectly
Confusing node labels

Trap Explanation:

PITFALL

Candidates may pick smaller child depths or sum depths instead of root's max depth.

Interviewer Note:

CONTEXT

Tests ability to reason backward from memoization cache to input tree depth.

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Given the following memoization cache after computing maxDepth on a binary tree: memo = {nodeA: 3, nodeB: 2, nodeC: 1} If nodeA is the root, nodeB is its left child, and nodeC is nodeB's left child, what is the maximum depth of the tree?

Step 1: Interpret memo values

Step 2: Confirm root depth

Final Answer:

Quick Check:

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