AoC 2023 day 15 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

use feature         qw(say);
use List::AllUtils  qw(firstidx indexes reduce);

sub hash ($) { reduce {(($a+$b)*17) % 256} (0, map {ord} split(//, shift)) };

my @Boxes;
my $part1 = 0;
foreach (map {chomp; split /,/} <>) {
    my ($label, $op, $foc) = m#(\w+)([=-])(\d?)#;

    $part1 += hash $_;
    my $box = hash $label;

    # Look for label in box:
    my $idx = firstidx { $label eq $_->[0] } $Boxes[$box]->@*;

    if ($op eq '-') {
        splice( $Boxes[$box]->@*, $idx, 1 )  if ($idx != -1);   # - remove lens
    } elsif ($idx != -1) {
        $Boxes[$box][$idx] = [$label, $foc];                    # = replace lens
    } else {
        push( $Boxes[$box]->@*, [$label, $foc] );               # = add lens
    }
}

my $part2 = 0;
foreach my $i (indexes {defined} @Boxes) {
    $part2 += ($i+1) * ($_+1) * $Boxes[$i][$_][1] foreach (0 .. $Boxes[$i]->$#*);
}

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