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Palindrome Check in Any Language

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Your question is Palindrome Check in Any Language. Start with the requirements on the right.

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Problem

For a text validation utility in a 3Pillar project, determine whether an input string is a palindrome. Compare only alphanumeric characters, ignoring spaces, punctuation, and letter casing.

Formal Specification

Implement is_palindrome(s), which accepts a string s and returns a boolean. Return True when the normalized sequence of alphanumeric characters reads identically from left to right and right to left. Return True for an empty normalized sequence.

Use a two-pointer approach that compares characters from both ends toward the center. Do not use slicing to reverse the entire string in the primary solution.

Constraints

  • 1 <= len(s) <= 2 * 10^5
  • s contains printable ASCII characters
  • Letters are compared case-insensitively
  • Non-alphanumeric characters are ignored

Function Signature

def is_palindrome(s):
Your solutionPython 3
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