#!/usr/bin/perl

use strict;
use warnings;

my @array = (1,2,3,6,4,5,7,8,9);
# UPDATED again, numeric sort
my $smallest = (sort {$a <=> $b} @array)[0];
my $stored = shift @array;

# UPDATED per bug report in reply
# if ($stored != $smallest) {
if ($stored != $smallest && $stored + 1 != $array[0]) {
	print "$stored appears to be in the wrong position\n";
	exit;
}

foreach my $i (0 .. $#array) {
	if ($stored != $array[$i] - 1) {
		if ($array[$i] + 1 != $array[$i + 1]) {
			print "$array[$i] appears to be in the wrong position\n";
			last;
		}
	}
	$stored = $array[$i];
}