[FEATURE]: Add Morris Traversal Algorithm

[aniket866]

Motivation

Describe your change:

• [x] Add an algorithm?
• [ ] Fix a bug or typo in an existing algorithm?
• [ ] Documentation change?

Checklist:

• [x] I have read [CONTRIBUTING.md](https://github.com/TheAlgorithms/Javascript/blob/master/CONTRIBUTING.md).
• [x] This pull request is all my own work -- I have not plagiarized.
• [x] I know that pull requests will not be merged if they fail the automated tests.
• [x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [x] All new JavaScript files are placed inside an existing directory.
• [x] All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames. Example: UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or another similar explanation. Example: [Morris Traversal - Wikipedia](https://en.wikipedia.org/wiki/Threaded_binary_tree#Morris_traversal)
• [ ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.
• [ ] closes

Examples

        7
       / \
      5   8
     / \
    3   6
         \
          9

Traversal order (Inorder: Left → Root → Right): Step 1: Visit leftmost node → 3 Step 2: Back to parent → 5 Step 3: Move to right subtree → 6 Step 4: Right child of 6 → 9 Step 5: Back to root → 7 Step 6: Right child of root → 8

Final output sequence: 3, 5, 6, 9, 7, 8

Possible workarounds

Possible Workarounds – Conceptual Illustration

Method | Space Complexity | Notes -- | -- | -- Recursive Inorder Traversal | O(h) | Uses call stack; simple but not O(1) Iterative Inorder with Stack | O(h) | Explicit stack; simulates recursion Threaded Binary Tree | O(1) | Permanently modifies tree pointers for threads

Visual analogy:

• Recursive / Stack → climbing stairs with a backpack (stack grows with height).

• Morris Traversal → climbing stairs using only your hands on rails (no extra backpack).

• Threaded Tree → installing permanent rails on stairs (extra setup, but efficient traversal).

Additional information

Additional Information – Illustration

Key Points about Morris Traversal:

Memory Efficient: Uses O(1) extra space, unlike recursion or stack.

Inorder Traversal: Left → Root → Right.

Temporary Tree Modification: Creates “threads” to revisit nodes.

Future Extension: Preorder Morris Traversal is possible with minor changes.

Reference: Wikipedia → Threaded binary tree / Morris Traversal.

Conceptual Analogy:

Normal Traversal (Stack/Recursion) → Carrying bags for each level Morris Traversal → Using built-in tree connections temporarily, no bags Threaded Tree → Installing permanent pathways for future traversals

[SaadArqam]

I want to work on this issue, Please assign me this issue

[SaadArqam]

I have raised the PR, please review it