Add Morris Tree Traversal implementation

[Ritesh1408]

Description of Change

Key Changes:
Morris traversal function for in-order traversal
Edge case handling for empty trees and single-node trees

Testing:
Included tests:

Simple binary trees
Skewed trees (left and right)
Complex trees with varying node configurations

Sample Test Cases
Basic Tree with Depth 2:

Input Tree:

1

/
2 3

Expected In-Order Traversal Output: 2 1 3
Complete Tree with Depth 3:

Input Tree:

  1
/   \

2 3
/ \ /
4 5 6 7

Expected In-Order Traversal Output: 4 2 5 1 6 3 7
Left-Skewed Tree:

Input Tree:

1

/
2
/
3
/ 4

• Expected In-Order Traversal Output: 4 3 2 1

Right-Skewed Tree:

Input Tree:

1

2

3

4
Expected In-Order Traversal Output: 1 2 3 4
Tree with Only Leaf Nodes on Left Subtree:

Input Tree:

  1
/   \

2 3
/
4
Expected In-Order Traversal Output: 4 2 1 3
Tree with Multiple Levels and Mixed Branching:

Input Tree:

     1
   /   \
  2     3
 / \     \
4   5     6
     \
      7

Expected In-Order Traversal Output: 4 2 5 7 1 3 6

Validation Steps

Memory Efficiency Check: Ensure that the Morris traversal function is not allocating additional memory (stacks or recursion frames) and maintains constant space usage, as it modifies the tree structure for in-order traversal.

Edge Case Handling:

Empty Tree: Input -1 as the first data point to create an empty tree and confirm that Morris traversal handles it gracefully.

Single Node Tree: Input only one node, ensuring the traversal output is the value of that single node.

Output Verification: Compare the Morris traversal output to expected in-order traversal results for each case to confirm accuracy.
Notes: Please verify the in-order traversal output matches expected values for different binary tree structures.

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes: