Collate sequence counter for Perl

collatz-sequence.pl

use strict;
use warnings;

sub collatz_count_until_1 {
    my $n = shift;
    my $count = 0;
    while ($n != 1) {
        $n = (($n % 2 == 0) ? ($n/2) : (($n*3) + 1));
        $count++;
    }
    return $count;
}

my $max;
foreach my $x (1..300000) {
    my $length = collatz_count_until_1($x);
    if (!defined($max) || $max->[0] < $length) {
        $max = [$length, $x];
    }
}

printf("Maximum stopping distance %d, starting number %d\n", $max->[0], $max->[1]);