Valid Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Tags: String

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Solution

class Solution:
    def isPalindrome(self, s: str) -> bool:
        left = 0
        right = len(s) - 1
        while left < right:
            while left < right and not s[left].isalnum():
                left += 1
            
            while left < right and not s[right].isalnum():
                right -= 1
            
            if s[left].lower() != s[right].lower():
                return False
            
            left += 1
            right -= 1
        return True