Bug Report for is-palindrome

[devansh-m100]

Bug Report for https://neetcode.io/problems/is-palindrome

Please describe the bug below and include any steps to reproduce the bug or screenshots if possible.

The 2nd solution Two Pointer based given in solution tab by NeetCode itself, is a buggy code and it fails when clicked submit button. The actual update is to be done in case of - the r > 1 is to be replaced by l < r in the 2nd inner while loop even.

Given Python model solution in solution tab -

class Solution:
def isPalindrome(self, s: str) -> bool:
l, r = 0, len(s) - 1

    while l < r:
        while l < r and not self.alphaNum(s[l]):
            l += 1
        while r > l and not self.alphaNum(s[r]):
            r -= 1
        if s[l].lower() != s[r].lower():
            return False
        l, r = l + 1, r - 1
    return True

def alphaNum(self, c):
    return (ord('A') <= ord(c) <= ord('Z') or
            ord('a') <= ord(c) <= ord('z') or
            ord('0') <= ord(c) <= ord('9'))

Correct model solution to update in solution tab -

class Solution:
def isPalindrome(self, s: str) -> bool:
l, r = 0, len(s) - 1

    while l < r:
        while l < r and not self.isAlphaNum(s[l]):
            l += 1
        while l < r and not self.isAlphaNum(s[r]):
            r -= 1
        if s[l].lower() != s[r].lower():
            return False
        l, r = l + 1, r - 1
    return True

def isAlphaNum(self, c):
    return (
        ord('A') <= ord(c) <= ord('Z') or
        ord('a') <= ord(c) <= ord('z') or
        ord('0') <= ord(c) <= ord('9')
    )