  Recently, Aum\"uller and Dietzfelbinger proposed a version of a dual-pivot
quicksort, called "Count", which is optimal among dual-pivot versions with
respect to the average number of key comparisons required. In this note we
provide further probabilistic analysis of "Count". We derive an exact formula
for the average number of swaps needed by "Count" as well as an asymptotic
formula for the variance of the number of swaps and a limit law. Also for the
number of key comparisons the asymptotic variance and a limit law are
identified. We also consider both complexity measures jointly and find their
asymptotic correlation.
