AoC 2021 day 3, part 2 (Perl)

#!/usr/bin/perl

use strict;
use warnings;

use List::AllUtils qw(true product);

sub filter {
    my ($negate, @list) = @_;

    for (my $i = 0; @list > 1; $i++) {
        my $ones = true { $_->[$i] } @list;
        my $next = ($ones >= (@list / 2)) ^ $negate;

        @list = grep { $_->[$i] == $next } @list;
    }

    return (oct("0b" . join('', @{$list[0]})));
}

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

print "Part 2: ", (product map {&filter( $_, @input )} (0,1)), "\n";