Implement Morris Traversal for In-Order Traversal

Description

Morris Traversal is a space-efficient algorithm for performing in-order traversal of a binary tree without using recursion or a stack. It achieves O(1) space complexity by temporarily modifying the tree structure using threaded binary trees.

Tasks

1. Implement Morris Traversal for in-order traversal.
2. Add unit tests to verify the correctness of the implementation.

References

• Morris Traversal Wikipedia