Robbie Hatley's Solutions, in Perl, for The Weekly Challenge #303 ("3-Digits Even" and "Delete and Earn")

For those not familiar with "The Weekly Challenge", it is a weekly programming puzzle with two parts, cycling every Sunday. You can find it here:

The Weekly Challenge

The Weekly Challenge for the week of 2024-01-06 through 2025-01-12 is #303.

The tasks for challenge #303 are as follows:

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Task 303-1: "3-Digits Even"
Submitted by: Mohammad Sajid Anwar
You are given a list (3 or more) of positive integers, @ints.
Write a script to return all even 3-digits integers that can be
formed using the integers in the given list.

Example #1:
Input: @ints = (2, 1, 3, 0)
Output: (102, 120, 130, 132, 210, 230, 302, 310, 312, 320)

Example #2:
Input: @ints = (2, 2, 8, 8, 2)
Output: (222, 228, 282, 288, 822, 828, 882)

This looks like yet another job for my favorite CPAN module, "Math::Combinatorics". I'll first extract the digits from @ints and push them to an array "@digits", then I'll grab all 3-combinations of @digits, then generate all permutations of each 3-combination, join, discard any beginning with 0, and discard any with odd final digit. Any that remain, I'll push to an array "@tde", then return a sorted, deduped copy of @tde.

Robbie Hatley's Perl Solution to The Weekly Challenge 303-1

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Task 303-2: "Delete and Earn"
Submitted by: Mohammad Sajid Anwar
You are given an array of integers, @ints. Write a script to
return the maximum number of points you can earn by applying
the following operation some number of times:
Pick any ints[i] and delete it to earn ints[i] points.
Afterwards, you must delete every element equal to
(ints[i] - 1) and every element equal to (ints[i] + 1).

Example #1:
Input: @ints = (3, 4, 2)
Output: 6
Delete 4 to earn 4 points. (Also delete all 3s and 5s.)
Finally delete 2 to earn 2 points.

Example #2:
Input: @ints = (2, 2, 3, 3, 3, 4)
Output: 9
Delete a 3 to earn 3 points. (Also delete all 2s and 4s.)
Delete a 3 again to earn 3 points.
Delete a 3 once more to earn 3 points.

Like most "minima" and "maxima" problems, this begs for recursion, so as to try all possibilities, seeking which yields minimum or maximum results. The trick is, whether/how to pass "results so far" to each recursive level. I think in this case, since we're finding a maximum within integer scores, I'll make a recursive subroutine "scores" that returns a list of all scores, then feed that list to the "max" function from CPAN module "List::Util".

Robbie Hatley's Perl Solution to The Weekly Challenge 303-2

That's it for challenge 303; see you on challenge 304!