Bird
Raised Fist0

In the following BFS-based deserialization code snippet, which line contains the subtle bug that causes incorrect tree reconstruction when the input string is empty?

medium🐞 Bug Identification Q7 of Q15
Tree: Depth-First Search - Serialize and Deserialize Binary Tree
In the following BFS-based deserialization code snippet, which line contains the subtle bug that causes incorrect tree reconstruction when the input string is empty?
ALine accessing vals[i] without checking if i < len(vals)
BLine splitting data string into vals list
CLine checking if data is empty and returning None
DLine appending node.left and node.right to queue
Step-by-Step Solution
Solution:

  1. Step 1: Identify potential index error

    In the while loop, vals[i] is accessed without verifying i < len(vals), which can cause IndexError if input is empty or truncated.

  2. Step 2: Confirm bug impact

    This causes runtime error or incorrect tree reconstruction on empty or malformed input.

  3. Final Answer:

    Option A -> Option A

  4. Quick Check:

    Bounds check missing before accessing vals[i] [OK]
Quick Trick: Check array bounds before accessing vals[i] [OK]
Common Mistakes:
MISTAKES
  • Assuming input always valid
  • Ignoring index out of range errors
Trap Explanation:
PITFALL
  • Candidates overlook missing bounds check, causing subtle runtime errors.
Interviewer Note:
CONTEXT
  • Tests candidate's ability to spot subtle bugs in deserialization code.
Master "Serialize and Deserialize Binary Tree" in Tree: Depth-First Search

3 interactive learning modes - each teaches the same concept differently

Try ItSolutionTrace

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More Tree: Depth-First Search Quizzes
Balanced Binary Tree - Balanced Binary Tree - Quiz 2easy Binary Tree Postorder Traversal - Binary Tree Postorder Traversal - Quiz 8hard Construct Tree from Inorder and Postorder - Construct Tree from Inorder and Postorder - Quiz 6medium Construct Tree from Preorder and Inorder - Construct Tree from Preorder and Inorder - Quiz 12easy Diameter of Binary Tree - Diameter of Binary Tree - Quiz 8hard Lowest Common Ancestor of Binary Tree - Lowest Common Ancestor of Binary Tree - Quiz 15hard Lowest Common Ancestor of Binary Tree - Lowest Common Ancestor of Binary Tree - Quiz 3easy Maximum Depth of Binary Tree - Maximum Depth of Binary Tree - Quiz 6medium Path Sum II (All Root-to-Leaf Paths) - Path Sum II (All Root-to-Leaf Paths) - Quiz 2easy Path Sum II (All Root-to-Leaf Paths) - Path Sum II (All Root-to-Leaf Paths) - Quiz 5medium