Robbie Hatley's Solutions, in Perl, for The Weekly Challenge #332 (“Binary Date” and “Odd Letters”)

For those not familiar with "The Weekly Challenge", it is a weekly programming puzzle with two parts, with a new pair of tasks each Monday. You can find it here:

The Weekly Challenge

The Weekly Challenge for the week of 2025-07-28 through 2025-08-03 is #332

The tasks for challenge #332 are as follows:

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Task 332-1: Binary Date
Submitted by: Mohammad Sajid Anwar
You are given a date in the format YYYY-MM-DD.
Write a script to convert it into binary date.

Example #1:
Input: $date = "2025-07-26"
Output: "11111101001-111-11010"

Example #2:
Input: $date = "2000-02-02"
Output: "11111010000-10-10"

Example #3:
Input: $date = "2024-12-31"
Output: "11111101000-1100-11111"

To solve this, I'll make two subroutines: "dec2bin" which converts positive integers expressed as strings of decimal digits into strings of binary digits, and "date2bin" which changes all clusters of digits in a string to their binary equivalents by calling "dec2bin" in "s/(\d+)/dec2bin($1)/egr".

Robbie Hatley's Perl Solution to The Weekly Challenge 332-1

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Task 332-2: Odd Letters
Submitted by: Mohammad Sajid Anwar
You are given a string. Write a script to find out if each
letter in the given string appeared odd number of times.

Example #1:
Input:  "weekly"
Output: false

Example #2:
Input:  "Perl"
Output: true

Example #3:
Input:  "challenge"
Output: false

I'll use a hash to keep track of the number of times each letter appears, then I'll use the "none" function from CPAN module "List::Util" to determine if none of the keys of the hash have even values.

Robbie Hatley's Perl Solution to The Weekly Challenge 332-2

That's it for challenge 332; see you on challenge 333!