Added HappyNumber algorithm in maths section (#6571)

* Added HappyNumber algorithm in maths section

* Fix Checkstyle: remove trailing spaces in HappyNumber

* Fix formatting: remove trailing spaces and apply clang-format

* Update HappyNumberTest.java

* Removed old HappyNumbersSeq.java as replaced by new HappyNumber.java

Ruturaj Jadhav committed 10mo ago

3c071c4e08e03910045634a80039ac47401f1a58

Parent: e788111

Committed by GitHub <noreply@github.com> on 10/9/2025, 5:31:56 PM