Worst-case performance of quickSort / getPivot

[bearophile]

Chris Cain:

> Also, to do this (in reasonable time) I had to create a new 
> range which I called "FastDice" ... it does the same as 
> std.random.dice, but is intended for cases where you'll be 
> throwing dice throws often on the same data, so it does a bit 
> of precomputation (creating a cumulative sum array)

See also:
http://d.puremagic.com/issues/show_bug.cgi?id=5849

Bye,
bearophile