Python Palindrome Function | Dataford Interview Questions

SAS Viya validation tools may receive identifiers and messages with inconsistent capitalization or punctuation. Write a function that determines whether a string is a palindrome after converting letters to lowercase and ignoring all non-alphanumeric characters.

Formal Specification

Implement is_palindrome(s), where s is a Python string. Return True if the normalized string reads the same from left to right and right to left. Return False otherwise. A normalized string contains only lowercase letters and digits.

Use a two-pointer approach that compares characters from both ends without creating a reversed copy of the input.

Constraints

1 <= len(s) <= 2 * 10^5
s contains printable ASCII characters
The string may contain letters, digits, spaces, and punctuation
An empty normalized string is considered a palindrome

Function Signature

def is_palindrome(s):

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