sub stoogesort {
	my (@lst) = @_;

	if ($lst[-1] < $lst[0]) {
		# swap
		@lst[0, -1] = @lst[-1, 0];
	}

	return @lst if (@lst < 3);

	# thirds
	my $zero  = 0;
	my $one   = int(@lst / 3);
	my $two   = int($#lst * 2 / 3);
	my $three = $#lst;

	for my $range (
		[ $zero .. $two   ],
		[ $one  .. $three ],
		[ $zero .. $two   ] ) {
		@lst[ @$range ] = stoogesort( @lst[ @$range ] );
	}

	return @lst;
}

my @list = (1, 2, 3, 9, 6, 4, 5, 7, 0);

print join(" ", stoogesort(@list)), "\n";