Palindrome Detection Coding | Dataford Interview Questions

During LTTS quality engineering validation, test identifiers may contain spaces, punctuation, and mixed case. Write a function that returns whether an identifier is a palindrome after ignoring non-alphanumeric characters and letter case.

A palindrome reads identically from left to right and right to left after normalization. For example, "No lemon, no melon" is a palindrome because its normalized form is "nolemonnomelon".

Formal Specification

Implement is_palindrome(text).

Input: text, a string containing letters, digits, spaces, and punctuation.
Output: A boolean. Return true when the normalized string is a palindrome, otherwise return false.

Do not build a separate normalized string. Compare characters in place using two pointers.

Constraints

0 <= len(text) <= 100,000
text contains printable ASCII characters
Comparison ignores case and non-alphanumeric characters
Empty and punctuation-only strings return true

Function Signature

def is_palindrome(text):

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