completed trees - 1

[yashhh-23]

No description provided.

[super30admin]

Validate Binary Search Tree (validateBST.java)

Strengths:

• Correctly implements the inorder traversal BST validation technique
• Clear and informative comments explaining the approach
• Good variable naming and code organization
• Properly handles the initial case where prev is null

Areas for Improvement:

• Consider adding early termination: once flag is set to false, you could return immediately to avoid unnecessary recursive calls. This won't change the O(n) worst-case time but can save work in invalid BST cases discovered early.
• The instance variable approach works but could also be implemented with a wrapper method or passed parameters for potentially cleaner encapsulation.

Overall, this is a solid solution that demonstrates good understanding of BST properties and inorder traversal.

VERDICT: PASS

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Construct Binary Tree from Preorder and Inorder Traversal (bstfromprepost.java)

Strengths:

• Clean, well-documented solution with clear comments
• Correctly implements the standard algorithm for this problem
• Good use of a hash map to achieve O(1) lookups
• Proper handling of base case and recursive structure

Areas for Improvement:

• The idx variable is an instance variable that gets reset in buildTree. Consider making it a parameter in the helper method for better encapsulation and thread-safety
• Could add null checks for edge cases (though constraints guarantee valid input)
• The code could benefit from more descriptive comments in the recursive helper

Minor Suggestions:

• Consider using Map<Integer, Integer> interface type instead of concrete HashMap for better programming to interfaces
• The comment header mentions "bstfromprepost" but the problem is about preorder/inorder, not postorder - ensure file/class naming is consistent with the problem

Overall, this is a solid solution that correctly solves the problem with optimal time complexity.

VERDICT: PASS