LeetCode-125: Two Pointer Is Palindrome

[WazedKhan]

Summary by CodeRabbit

• New Features
  • Added a new algorithmic solution for “Valid Palindrome,” including case-insensitive matching and automatic ignoring of non-alphanumeric characters.
• Tests
  • Added a comprehensive pytest suite for the new solution, covering edge cases, punctuation, numeric/alphanumeric mixes, and longer phrases.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 87e76973-ced6-4e68-a65e-3cc42455e68d

📥 Commits

Reviewing files that changed from the base of the PR and between 342d097 and 684ba0a.

📒 Files selected for processing (1)

• tests/test_leetcode_easy.py

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📝 Walkthrough

Walkthrough

A new file LeetCode/easy/is_palindrome_125.py is added containing a Solution class with an isPalindrome method using a two-pointer approach. The implementation skips non-alphanumeric characters, performs case-insensitive comparisons, and returns False on the first mismatch or True when pointers meet. Comprehensive parametrized tests validate the implementation across punctuation, casing, digits, empty strings, and palindrome/non-palindrome phrases.

Changes

Valid Palindrome (LeetCode 125)

Layer / File(s)	Summary
Two-pointer isPalindrome implementation LeetCode/easy/is_palindrome_125.py	Adds Solution.isPalindrome(s: str) -> bool using two pointers that skip non-alphanumeric characters, compare lowercased characters from both ends, and return False on mismatch or True when pointers meet.
Parametrized test coverage tests/test_leetcode_easy.py	Introduces test_is_palindrome_125 with 17+ test cases covering classic palindromes, empty/blank strings, single characters, punctuation handling, case insensitivity, numeric content, and mixed phrases.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 A string from both ends I shall peek,
Skipping symbols, left and right I seek,
Lowercased letters line up just so,
If they all match — a palindrome, ho!
True or False, the rabbit hops free~ 🌿

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: introducing a LeetCode 125 solution using a two-pointer approach to check if a string is a palindrome.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch leetcode-125-is-palindrome-two-pointers

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Note

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✅ Unit tests committed locally. Commit: 684ba0af86105bcf9f59454a2f6b820b5642ca6d