Complete Trees-2

[satish-paraddi]

No description provided.

[super30admin]

Construct Binary Tree from Inorder and Postorder Traversal (Problem_1.py)

Strengths:

1. Your solution correctly implements the optimal O(n) algorithm using a hashmap for inorder index lookup.
2. The recursive approach correctly builds the right subtree before the left subtree, which is essential for the postorder traversal pattern.
3. The code is concise and readable.
4. You confirmed the solution runs successfully on Leetcode.

Areas for Improvement:

1. Indentation issue: The buildTree method has an extra level of indentation (8 spaces instead of 4). This is a minor style issue but should be fixed for PEP 8 compliance.
2. Explicit return: In the helper function, when start > end, you should explicitly return None instead of just return for better clarity.
3. Missing imports: While Leetcode provides these, in a standalone file you'd need to import List, Optional, and TreeNode.
4. Method organization: Consider defining helper as a nested function or using @staticmethod if you don't need self, or keep it as a method but be consistent with the indentation.

Overall: Your solution is correct, efficient, and demonstrates a good understanding of the problem. The algorithm matches the reference solution's approach.

VERDICT: PASS

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Sum Root to Leaf Numbers (Problem_2.py)

EVIDENCE: [Evidence from the student's solution or test cases]

EVIDENCE:

• The student's solution uses a recursive approach that mirrors the reference solution's logic.
• The student's solution returns the sum directly from the recursive function rather than using a class variable.
• The returning 0 for null nodes ensures that null subtrees don't contribute to the sum.
  • This is a clean and Pythonic approach.
• The student's solution correctly handles the base case for leaf nodes.
• The currSum = currSum * 10 + root.val correctly builds the number along the path.
  currSum is correctly propagated to both children.
  currSum is correctly propagated to both children.

VERDICT: NEEDS_IMPROVEMENT