Comments on: Red-Black Tree revisited, deleting nodes

By: Ferad

Ferad — Mon, 19 Oct 2009 14:32:06 +0000

I think the method PerformHardDelete has a bug. It does not consider the case when the node being deleted is the root (i.e. the only last node). Then it gives null reference exception at

if (current.ParentDirection == Direction.LEFT)
–>>> current.ParentNode.RightNode = null;
else

I will need to make a closer look if explicit check will solve the problem.

By: Banausenrepublik » Blog Archive » Left-leaning red-black trees

Banausenrepublik » Blog Archive » Left-leaning red-black trees — Sat, 22 Aug 2009 18:07:54 +0000

[...] von Hilfsknoten (”NIL”) und Referenzierung der Mutterknoten verkompliziert. Eine komplette Implementierung der delete-Methode ist sowieso nur schwer zu finden. Auch in der ursprünglichen [...]

By: Marko Gavranovic

Marko Gavranovic — Sun, 01 Feb 2009 20:23:20 +0000

Thx, very good explaination and illustration about deleting a black leaf in RBT (i think this is a only web-site with that kind of explanation – its better explained than on Wikipedia)

By: Jack Altiere

Jack Altiere — Mon, 22 Dec 2008 20:34:59 +0000

That’s an interesting paper, I didn’t come across that while I was working on this. I’ll have to dig into it. Thanks for the link!

By: Laurion Burchall

Laurion Burchall — Mon, 22 Dec 2008 20:30:30 +0000

Sedgewick has fine-tune red-black trees and has a paper on left-leaning red-black trees (released earlier this year).

http://www.cs.princeton.edu/~rs/talks/LLRB/LLRB.pdf

The basic idea is to eliminate the case where the right child is red and the left child is black (using the existing rotation mechanism). This simplifies the code to do inserts and deletes while preserving the time complexity.

If you try the techniques in the paper, I think you’ll find your code gets simpler.