Trees-2 completed

[sujaygijre]

No description provided.

[super30admin]

Strengths:

• The solution correctly implements the recursive approach to construct the binary tree from inorder and postorder traversals.
• The use of an unordered_map to store inorder indices is efficient and allows for O(1) lookups.
• The recursion is handled correctly by first building the right subtree and then the left subtree, which is necessary because the postorder traversal processes the root after the left and right subtrees, but we are traversing the postorder array backwards.

Areas for Improvement:

• The variable name um for the unordered_map is not very descriptive. Consider renaming it to something like inorderIndexMap to make the code more readable.
• The helper function parameters left and right could be renamed to start and end to match the common convention and make it clear that they represent the current segment of the inorder array being processed.
• Although not necessary, adding comments to explain the steps (especially why the right subtree is built before the left) would be helpful for maintainability.
• The solution uses a class member variable postIndex which is reset in the buildTree function. This is acceptable, but note that if the same Solution instance is reused, it might lead to issues. However, in the context of LeetCode, this is typically safe as the instance is created per test case. Alternatively, you could pass the index by reference or use a local variable and pass it recursively to avoid class state, but the current approach is standard.