#!/usr/bin/perl

use strict;
use warnings;
use Algorithm::FastPermute;

#uncomment the following line and comment out the next to see the diff
#my @array = (0 .. 7);
my @array = (100_000 .. 100_007);
my ($key, %perm);

permute {$key = join '',@array;$perm{$key} = 1} @array;
print scalar %perm;