Shellsort, like the Mergesort and Quicksort, among others, divides a
data set into subsets, sorts the subsets, and then recombines these
sorted subsets. A Shellsort's average performance is thought to be
about n^{3/2}. The exact complexity of this algorithm is still
being debated and is far too advanced for this presentation. Suffice
to say that for midsized data sets it performs nearly as well if not
better than the faster (n log n) sorts.
