Trees-1 solution

[Simranb10]

No description provided.

[super30admin]

Validate BST (ValidateBST.java)

Strengths:

1. Excellent approach using bounds checking - this is a classic and elegant solution for BST validation
2. Clean, readable code with good variable naming (lower, upper)
3. Proper base case handling
4. Correct recursive logic for both left and right subtrees
5. Well-commented with time/space complexity

Areas for Improvement:

1. Consider adding a main method or test cases to demonstrate the solution's correctness
2. Could add null checks for the root parameter if defensive programming is desired (though not strictly required given problem constraints)
3. The solution could benefit from inline comments explaining the bounds logic for future maintainability

Minor Note:
The comment "Time Complexity: O(n)" and "Space Complexity: O(h)" are good practices, but could also mention that h can be O(n) in worst case (skewed tree), making space complexity O(n) in worst case.

VERDICT: PASS

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

Strengths:

• Clean and well-structured solution that mirrors the optimal approach
• Good use of HashMap for O(1) value-to-index lookup
• Clear variable naming and logical code organization
• Proper handling of base case (start > end)
• Correct boundary calculations for recursive calls

Areas for Improvement:

• Consider declaring the map as Map<Integer, Integer> instead of HashMap<Integer, Integer> for better programming practice (programming to interfaces)
• The solution is already very close to optimal, so no major changes needed

VERDICT: PASS