Ha, this is my article. Believe me when I say I had developed a truly remarkable solution of this problem which this blog post is too small contain.

More believably, this is a very basic introduction to the problem. More complex solutions are possible but are very tied to the specific datastructure and access patterns. It is hard to generalize advice once the problems get more involved so I just declared them out-of-scope and only mentioned some ideas in passing.

Maybe I will write a part II sometime. The comments here are interesting.