Problem 14

#!/usr/bin/perl
use strict;
use warnings;
 
my $i=999999;
my $max=0; 
my $maxchain=0;
 
sub collatz
{
    my $n = shift;
    my $count = 1;
    while($n > 1){
        if($n % 2 == 0){
            $n = $n/2;
        } else{
            $n = 3*$n + 1;
        }
        $count++;
    }
    return $count;
}
 
while($i > 1){
    my $value = collatz($i);
    if ($value > $maxchain){
        $max = $i;
        $maxchain = $value;
    }
    $i--;
}
 
print "$max\n";