Given the following partial output of the isMirror function calls during recursion: isMirror(node with val=2, node with val=2) -> True isMirror(node with val=3, node with val=3) -> False What can be inferred about the original tree structure?

hard🔄 Reverse Engineer Q9 of Q15

Tree: Depth-First Search - Symmetric Tree (DFS Approach)

AThe tree is symmetric with identical leaf nodes.

BThe tree has matching root children but asymmetric leaf subtrees.

CThe tree is empty.

DThe tree has different root values.

Step-by-Step Solution

Solution:

Step 1: Interpret isMirror results
isMirror returns True for root children with val=2, but False for leaf nodes with val=3.
Step 2: Deduce tree structure
Root children match, but leaf subtrees differ, indicating asymmetry at lower levels.
Final Answer:
Option B -> Option B
Quick Check:
Partial symmetry broken at leaf nodes [OK]

Quick Trick: True at root children, False at leaves means partial asymmetry [OK]

Common Mistakes:

MISTAKES

Assuming entire tree symmetric
Ignoring leaf node mismatch

Trap Explanation:

PITFALL

Candidates may misinterpret partial True results as full symmetry.

Interviewer Note:

CONTEXT

Tests ability to reason backwards from recursion outputs

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More Tree: Depth-First Search Quizzes

Given the following partial output of the isMirror function calls during recursion: isMirror(node with val=2, node with val=2) -> True isMirror(node with val=3, node with val=3) -> False What can be inferred about the original tree structure?

Step 1: Interpret isMirror results

Step 2: Deduce tree structure

Final Answer:

Quick Check:

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