First associations for me - sympathy, elegance (without even looking at the code), thought about that the data should be prepared (most likely sorted), thought

First associations for me - sympathy, elegance (without even looking at the code), thought about that the data should be prepared (most likely sorted), thought about that this might be one particular operation and [data structure] might imply that other operations could have different O's. Well, and finally I'll actually look at it (click on the link).