Palindrome With Edge Cases | Dataford Interview Questions

A text utility in the My BMW App needs to recognize palindromic user-entered text. Write a function that returns whether a string reads the same forward and backward after ignoring letter case, spaces, and non-alphanumeric characters.

Formal Specification

Implement is_palindrome(s), where s is a string. Return True if the filtered, case-insensitive sequence of letters and digits is identical in both directions. Return False otherwise. If filtering removes every character, return True.

Use a two-pointer approach that scans from both ends. You may use Python's isalnum() method to identify characters that should be compared.

Constraints

0 <= len(s) <= 10^5
The input may contain letters, digits, whitespace, and punctuation
Comparisons are case-insensitive
Only alphanumeric characters participate in comparisons

Function Signature

def is_palindrome(s):

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