Palindrome Runtime Optimization | Dataford Interview Questions

TRADER Corporation may need to validate normalized text in listing titles or search inputs. Given a string, determine whether it is a palindrome after ignoring case and removing all non-alphanumeric ASCII characters.

Return True if the remaining characters read identically from left to right and right to left. Return False otherwise.

Formal Specification

Implement is_palindrome(text), where text is a string and the return value is a boolean. Treat ASCII letters case-insensitively. Digits remain unchanged, and spaces, punctuation, and other non-alphanumeric characters are ignored.

You should optimize the solution for linear runtime and constant auxiliary space by comparing characters from both ends while moving toward the center.

Constraints

0 <= len(text) <= 100,000
text contains printable ASCII characters
An empty string is considered a palindrome
Do not modify the input string

Function Signature

def is_palindrome(text):

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