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Given the following partial output of a Path Sum II function: [[5, 4, 11, 2], [5, 8, 4, 5]], which of these trees and target sums could produce this output?

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Tree: Depth-First Search - Path Sum II (All Root-to-Leaf Paths)
Given the following partial output of a Path Sum II function: [[5, 4, 11, 2], [5, 8, 4, 5]], which of these trees and target sums could produce this output?
ATree with root=5, left=4->11->2, right=8->4->5, targetSum=22
BTree with root=5, left=4->11->2, right=8->4->5, targetSum=20
CTree with root=5, left=4->11->2, right=8->4->1, targetSum=22
DTree with root=5, left=4->11->7, right=8->4->5, targetSum=22
Step-by-Step Solution
Solution:

  1. Step 1: Verify sums of given paths

    Sum of [5,4,11,2] = 22; sum of [5,8,4,5] = 22.

  2. Step 2: Check tree structure consistency

    Tree with root=5, left=4->11->2, right=8->4->5, targetSum=22 matches both paths and sums exactly.

  3. Step 3: Identify correct option

    Option A matches the paths and target sum exactly.

  4. Final Answer:

    Option A → Option A

  5. Quick Check:

    Paths and sums must match target sum exactly [OK]
Quick Trick: Sum paths and verify tree structure [OK]
Common Mistakes:
MISTAKES
  • Ignoring sum mismatch
  • Assuming any similar tree fits output
Trap Explanation:
PITFALL
  • Candidates often overlook exact sum matching or confuse node values in paths.
Interviewer Note:
CONTEXT
  • Tests ability to reverse engineer input from output paths.
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