Completed Trees-2

[sarvanibaru]

No description provided.

[super30admin]

Strengths:

1. The solutions are correct and efficient.
2. The code is well-commented, explaining the approach clearly.
3. The use of a hashmap for the tree construction problem is appropriate and efficient.
4. The recursion is handled correctly in both problems.

Areas for Improvement:

1. In the tree construction problem, the helper method's parameters start and end are indices in the inorder array, but the parameter name end might be confused with the postorder array. Consider renaming the parameters to inStart and inEnd to make it explicit that they refer to the inorder array indices. This would improve readability and avoid confusion.
2. The variable index in the tree construction problem is declared as an instance variable. While this works, it would be better to avoid instance variables when possible to make the solution more thread-safe. Alternatively, you could pass the index as a parameter by reference (but in Java, you would need to use an array or a mutable object to simulate pass-by-reference). However, given the constraints of recursion, the current approach is acceptable.
3. In the sum root to leaf numbers problem, the method calculateSum uses a primitive integer for currNum, which is passed by value. This is efficient and correct. However, note that the same currNum value is shared in the recursion for left and right. This is fine because the value is not modified across recursive calls. But if you were to use a mutable object, it would be problematic. The current approach is good.

Overall, the solutions are excellent. The minor suggestion about parameter naming is just to enhance clarity.