Completed Trees1

[Keerthi0910]

[super30admin]

Validate Binary Search Tree (Problem1.java)

Strengths:

• Your solution correctly implements the in-order traversal approach to validate a BST.
• The logic is sound and matches the reference solution.
• You added a nice optimization with the if(flag) checks to short-circuit the traversal once an invalid BST is detected.
• The code is readable and well-structured.

Areas for improvement:

• The comments at the top of your file are incorrect. You wrote "O(n) space complexity" and "O(1) time complexity", but the actual complexities are O(n) time and O(h) space (where h is the height of the tree due to the recursion stack).
• Consider making the helper method private instead of public since it's an internal helper method.
• The if(flag) checks are a good optimization, but be aware that in the worst case (when the tree is valid), they don't provide any benefit. They're only useful when an invalid BST is detected early.

VERDICT: PASS

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

[Feedback for the instructor]

VERDICT: NEEDS_IMPROVEMENT