[mohamedTarek-143]

Summary of Changes

Fixed a bug in CircularLinkedList.InsertAfter where inserting a node after the current tail failed to update the tail pointer to the newly created node.

Motivation & Context

In a circular linked list tracked by a single tail pointer, the head of the list is defined as tail.Next. When calling InsertAfter(value, data) where value belongs to the current tail, the new node was correctly linked after tail, but tail itself was never reassigned to newNode. Consequently, the list structure became inverted: the newly inserted element was treated as the new head (tail.Next), and the old tail remained marked as the end of the list.

Checklist

[x] I have performed a self-review of my code
[x] My code follows the style guidelines of this project
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Comments in areas I changed are up to date
[ ] I have added comments to hard-to-understand areas of my code
[ ] I have made corresponding changes to the README.md

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 0 complexity · 0 duplication

Metric	Results
Complexity	0
Duplication	0

View in Codacy

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[Copilot]

🟡 Changes recommended

The new test is declared outside the CircularLinkedListTests class at namespace scope, causing C# error CS0116 and preventing the test project from compiling.

1 open issue

• Test method outside fixture prevents test project from compiling · New

What changed in this PR

This PR fixes CircularLinkedList<T>.InsertAfter so inserting after the tail updates the tail pointer and preserves the existing head.

Changes:

• Reassigns tail to the new node when inserting after the current tail.
• Adds a regression test checking head preservation, node order, and circular linkage.

File	Description
DataStructures/​LinkedList/​CircularLinkedList/​CircularLinkedList.cs	Updates the tail pointer after tail insertion.
DataStructures.Tests/​LinkedList/​CircularLinkedListTests.cs	Adds a regression test for insertion after a single-node list’s tail.

_{Review effort: Balanced}

[siriak]

Hi, still see the remaining formatting issues

[Copilot]

🟢 Approval recommended

No active review issues remain for the circular-list tail-pointer update and its regression test.

No open issues 🎉

1 resolved since last review

• Test method outside fixture prevents test project from compiling

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

There are no active review issues blocking the tail-insertion fix and its regression coverage.

No open issues 🎉

_{Review effort: Balanced}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.96%. Comparing base (96e2905) to head (f979a77).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #583      +/-   ##
==========================================
- Coverage   96.96%   96.96%   -0.01%     
==========================================
  Files         300      300              
  Lines       12598    12602       +4     
  Branches     1842     1843       +1     
==========================================
+ Hits        12216    12219       +3     
  Misses        242      242              
- Partials      140      141       +1     

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[siriak]

Looks good, thanks!

[mohamedTarek-143]

You are welcome :)