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Rahul Kumar Barnwal @rahulgithub-web

Top Interview 150: Valid Palindrome Challenge

Valid Palindrome problem: remove non-alphanumeric chars, convert to lowercase. Use two pointers to check if string is palindrome. Time complexity O(n), space complexity O(1).

Top Interview 150
The Valid Palindrome problem is a common challenge that tests your ability to process strings and work with character validation. Let’s tackle LeetCode 125: Valid Palindrome step by step.


  
  
  🚀 Problem Description

A phrase is a palindrome if, after:

Converting all uppercase letters to lowercase.
Removing all non-alphanumeric characters.

The phrase reads the same backward as forward.
Return true if the input string s is a palindrome; otherwise, return false.

  
  
  💡 Examples

Example 1

Input: s = "A man, a plan, a canal: Panama"  
Output: true  
Explanation: Aft...