Add array rotation utility

[Bhanubasyan]

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
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[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.01%. Comparing base (9d9e348) to head (ced68c8).

Files with missing lines	Patch %	Lines
...n/java/com/thealgorithms/others/ArrayRotation.java	91.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7586      +/-   ##
============================================
+ Coverage     82.00%   82.01%   +0.01%     
- Complexity     8280     8286       +6     
============================================
  Files           840      841       +1     
  Lines         25872    25896      +24     
  Branches       5053     5055       +2     
============================================
+ Hits          21216    21239      +23     
- Misses         3866     3867       +1     
  Partials        790      790              

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[mohithvardhan002]

What should happen when k is negative? In Java, % keeps the sign of the dividend, so a negative k can result in invalid indices during reverse(). Could we either normalize k to the range [0, n) or explicitly reject negative values, and add a test for this case?

[Bhanubasyan]

Handled negative k by normalizing it to the range [0, n) and added a test case covering negative rotation.

[mohithvardhan002]

Could we also add a test for rotateLeft() when k is greater than the array length? The current test only covers this case for right rotation, while left rotation has separate logic.

[Bhanubasyan]

Added a separate test for rotateLeft() when k is greater than the array length.

[Bhanubasyan]

Hi Mohith, Thank you for the detailed review and suggestions. I agree with all three points: - I’ll remove Trie.java from this PR and keep the PR focused specifically on the array rotation utility. - I’ll handle negative k by normalizing it to the valid range and add a corresponding test case. - I’ll add a test covering rotateLeft() when k is greater than the array length. I’ll make these changes and update the PR accordingly. Thanks again for the review!

…

On Mon, 5 Oct 2026 at 11:10, Mohith Vardhan Beedupalli < ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In src/main/java/com/thealgorithms/others/Trie.java <#7586 (comment)>: > @@ -0,0 +1,162 @@ +package com.thealgorithms.others; + +import java.util.ArrayList; +import java.util.List; + +public class Trie { Could we remove Trie.java from this PR? This PR is focused on adding the array rotation utility, but the Trie implementation seems unrelated to the main purpose of the change. Keeping it here makes the PR larger and also introduces additional code that doesn't have corresponding tests. I think it would be cleaner to move the Trie changes into a separate PR. ------------------------------ In src/main/java/com/thealgorithms/others/ArrayRotation.java <#7586 (comment)>: > + } + + /** + * Rotates the array to the right by k positions. + * + * @PARAM nums the input array + * @PARAM k number of rotations + */ + public static void rotateRight(int[] nums, int k) { + int n = nums.length; + + if (n == 0) { + return; + } + + k = k % n; What should happen when k is negative? In Java, % keeps the sign of the dividend, so a negative k can result in invalid indices during reverse(). Could we either normalize k to the range [0, n) or explicitly reject negative values, and add a test for this case? ------------------------------ In src/test/java/com/thealgorithms/others/ArrayRotationTest.java <#7586 (comment)>: > +public class ArrayRotationTest { + + @test + void shouldRotateArrayRightByTwoPositions() { + int[] values = {1, 2, 3, 4, 5}; + + ArrayRotation.rotateRight(values, 2); + + assertArrayEquals(new int[] {4, 5, 1, 2, 3}, values); + } + + @test + void shouldRotateArrayLeftByTwoPositions() { + int[] values = {1, 2, 3, 4, 5}; + + ArrayRotation.rotateLeft(values, 2); Could we also add a test for rotateLeft() when k is greater than the array length? The current test only covers this case for right rotation, while left rotation has separate logic. — Reply to this email directly, view it on GitHub <#7586?email_source=notifications&email_token=BCOZJDD7V65UGJ33Q2HTC3D5SMX33A5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTKNBQHE4TMMRYG432M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#pullrequestreview-5409962877>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BCOZJDBPFYQJU5GIDXCH4AT5SMX33AVCNFSNUABEKJSXA33TNF2G64TZHM3DGNBXG43DMMB3JFZXG5LFHM2TEOBXGMYTSOJTGSQXMAQ> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/BCOZJDAEYMZ2TPQDDPAXZND5SMX33A5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTKNBQHE4TMMRYG432M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android <https://github.com/notifications/mobile/android/BCOZJDEPCOOFIHC4AYKT7P35SMX33A5CNFSNUABKM5UWIORPF5TWS5BNNB2WEL2QOVWGYUTFOF2WK43UKJSXM2LFO4XTKNBQHE4TMMRYG432M4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: <TheAlgorithms/Java/pull/7586/review/5409962877 ***@***.*** com>

[mohithvardhan002]

Looks good. Logic is correct, tests cover the edge cases, and the earlier review comment about left rotation with k > n is addressed. Thanks!