Anagram Checking | Dataford Interview Questions

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Problem

Shelter Insurance systems may compare customer-entered text, such as names or reference phrases, without treating capitalization or punctuation as meaningful. Given two strings, determine whether they are anagrams after normalization.

Two strings are normalized by converting letters to lowercase and ignoring every character that is not a letter or digit. Return True if the normalized strings contain exactly the same characters with the same frequencies, otherwise return False.

Formal Specification

Implement are_anagrams(s, t):

Input: Two strings s and t containing printable ASCII characters.
Output: A Boolean. Return True when the normalized versions are anagrams, and False otherwise.
Repeated characters must occur the same number of times. Character order does not matter.

Constraints

0 <= len(s), len(t) <= 10^5
Inputs contain printable ASCII characters
Only letters and digits contribute to the comparison
The comparison is case-insensitive

Function Signature

def are_anagrams(s, t):