Validate Binary Search Tree and Construct Binary Tree from Preorder and Inorder Traversal

[anirudhv98]

Completed Trees-1, please review.

[super30admin]

Validate BST (Problem1.cs)

Strengths:

• Clean, readable implementation with clear variable naming
• Correct use of long type for bounds, which handles edge cases better than using int (the reference solution uses int and could potentially have overflow issues with extreme values)
• Good three-line explanation that accurately describes the approach
• Proper handling of the base case (null node returns true)

Areas for Improvement:

• The space complexity claim of O(1) is incorrect. Recursive solutions inherently use O(h) stack space. If O(1) space is required, an iterative approach with explicit stack or Morris traversal would be needed.
• Consider adding comments to explain the boundary logic, especially for future readers who might not immediately understand why min/max bounds work for BST validation.

VERDICT: PASS

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Construct Binary Tree from Preorder and Inorder Traversal (Problem2.cs)

Strengths:

• Clear and concise explanation in comments
• Good use of descriptive variable names
• Proper handling of base case
• Correct recursive logic for tree construction
• Well-documented approach

Areas for Improvement:

• The solution is already well-optimized. One minor suggestion would be to consider making the fields readonly or encapsulating them better, but this is a minor point.
• Could potentially add null checks for input arrays for robustness, though the problem constraints guarantee valid inputs.

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

VERDICT: PASS