AoC 2025 day 7 part 1 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

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

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

my $part1 = 0;
my %beams = map { $_ => 1 } indexes { $_ eq 'S' } @{shift @input};

while (my $row = shift @input) {
    my @splitters = indexes { $_ eq '^' } @$row;
    next if (!@splitters);

    my @splits = grep { exists $beams{$_} } @splitters;
    $part1 += @splits;

    foreach my $split (@splits) {
        delete $beams{$split};
        $beams{$split-1}++;
        $beams{$split+1}++;
    }
}

say "Part 1: $part1";