125. Valid Palindrome

To find if a palindrome is valid, we can filter out any characters and then check if forwards and backwards it is the same up to the halfway point.

class Solution:
    def isPalindrome(self, s: str) -> bool:
        converted = [c.lower() for c in s if c.isalnum()]
        mid = len(converted) // 2
        if len(converted) % 2 == 0:
            forwards = converted[:mid] 
        else:
            forwards = converted[:mid+1]
        backwards = converted[mid:][::-1]
        return forwards == backwards