Coding Challenge: Palindrome | Dataford Interview Questions

Medtronic CareLink may display alert or status text containing spaces, punctuation, and mixed capitalization. Write a function that determines whether the meaningful characters form a palindrome.

A string is a palindrome if it reads identically from left to right and right to left after converting letters to lowercase and ignoring every non-alphanumeric character.

Formal Specification

Implement is_palindrome(s), where s is a string. Return True if the normalized string is a palindrome, otherwise return False. Normalization must preserve digits, compare letters case-insensitively, and ignore spaces, punctuation, and other non-alphanumeric characters.

Use a two-pointer approach that scans inward from both ends. Avoid constructing a separate normalized string.

Constraints

0 <= len(s) <= 2 * 10^5
The input may contain letters, digits, whitespace, and punctuation.
Comparisons are case-insensitive.
Python's isalnum() determines which characters are alphanumeric.

Function Signature

def is_palindrome(s):

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