Tree: Depth-First Search - Invert Binary Tree
Given the final inverted tree where the root's left child is 7 and right child is 2, and the left subtree's left child is 9, what was the original root's left child?
Given the final inverted tree where the root's left child is 7 and right child is 2, and the left subtree's left child is 9, what was the original root's left child?
hard🔄 Reverse Engineer Q9 of Q15
Step-by-Step Solution
Solution:
Step 1: Understand inversion effect
Inversion swaps left and right children at every node.Step 2: Reverse swap at root
Final left child is original right child, so original left child is final right child, which is 2.Final Answer:
Option C -> Option CQuick Check:
Invert swaps children -> original left = final right [OK]
Quick Trick: Invert swaps children; reverse to find original [OK]
Common Mistakes:
MISTAKES- Confusing final left with original left
- Not reversing inversion logic
Trap Explanation:
PITFALL- Candidates often fail to reverse the inversion logic to find original structure.
Interviewer Note:
CONTEXT- Tests ability to reason backwards through tree inversion
Master "Invert Binary Tree" in Tree: Depth-First Search
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