AoC 2025, day 2 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

use feature         qw(say);
use List::Util      qw(sum);

my @input = map { chomp; map { [split /-/] } split /,/ } <>;

my $part1 = 0;
my $part2 = 0;

foreach my $range (@input) {
    my ($first, $last) = @$range;
    my %invalid;

    for (my $i = 1; "$i$i" <= $last; $i++) {
        my $num = "$i$i";

        $part1 += $num  if ($first <= $num <= $last);

        for ($num .= $i while ($num < $first); $num <= $last; $num .= $i) {
            $invalid{$num}++;
        }
    }

    $part2 += sum keys %invalid  if (%invalid);
}

say "Part 1: $part1";
say "Part 2: $part2";