#!/usr/bin/perl

use warnings;
use strict;

my $before = [qw(1 2 3 4 5 6 7 8 9 10)];
my $after  = [qw(2 3 4 5 1 6 7 8 9 10)];

my $len = @{$before}-1;

for (reverse @{$before}){
	print $before->[$len], "\t";
	print $after->[$len],  "\n";
	last if $before->[$len] != $after->[$len];
	$len--;
}

#$len++;
print "offset: $len\n";
print "element: $after->[$len]\n";