sub ldist {
	my @s = split //, shift;
	my @t = split //, shift;

	return scalar @t if scalar @s == 0;
	return scalar @s if scalar @t == 0;

	my (@prevColumn, @currColumn);

	@prevColumn = 0..scalar(@t);

	for my $s (0..$#s) {
		@currColumn = ( $s + 1 );
		for my $t (0..$#t) {
			push @currColumn, min(
				$currColumn[$t] + 1
				, $prevColumn[$t+1] + 1
				, $prevColumn[$t] + ($s[$s] eq $t[$t] ? 0 : 1)
			);
		}
		@prevColumn = @currColumn;
	}

	pop @currColumn
}

sub min {
	my $min = shift;

	for (@_) {
		$min = $_ if $_ < $min;
	}

	$min;
}