my %node = ();

sub idx {
	my $n = shift;
	my $index = 1;
	while (exists $node{$index}) {
		if (sin($n) < sin($node{$index})) {
			$index = $index*2;
		} else {
			$index = $index*2+1;
		}
	}
	$node{$index} = $n;
	return $index;
}

foreach my $n (1..10_000) {
	my $a = idx($n);
	print "$n $a\n";
}