#!/usr/bin/perl

use strict;
use warnings;

my @arr = (0..9);
my %hash;
@hash{@arr} = (0) x @arr;

sub scanit
{
	my $number = shift;
	my $cnt = 0;
	for (0..9)
	{
		foreach my $c (split //, $hash{$_})
		{
			$cnt++ if ($number == $c);
		}
	}
	$cnt+1;
}
	
my $solcount=0;
while (1)
{
	my $cond = 0;
	# update the counts
	for (my $i=9; $i>=0; $i--)
	{
		my $cnt = scanit($i);
		$hash{$i} = $cnt;
	}

	# check whether our solution is valid.
	for (0..9)
	{
		my $cnt = scanit($_);
	    $cond = 1 if ($hash{$_} != $cnt);
	}

	# print it if it is.
	if ($cond == 0)
	{
		my @print;
		for (1..9)
		{
			push @print, "of $_ "."s is $hash{$_}";
		}
		print "The number of 0s in this sentence is $hash{0}, " .
			join(", ", @print) . "\n";
		die;
	}
	else
	{
		$cond = 1;
	}
}