Stooge sort

Stooge sort is a recursive sorting algorithm. It is notable for its exceptionally bad time complexity of $$O(n^{\log 3/\log 1.5})$$ = $$O(n^{2.7095...})$$ The running time of the algorithm is thus slower compared to reasonable sorting algorithms, and is slower than bubble sort, a canonical example of a fairly inefficient sort. It is however more efficient than Slowsort. The name comes from The Three Stooges.

The algorithm is defined as follows:
 * If the value at the start is larger than the value at the end, swap them.
 * If there are three or more elements in the list, then:
 * Stooge sort the initial 2/3 of the list
 * Stooge sort the final 2/3 of the list
 * Stooge sort the initial 2/3 of the list again

It is important to get the integer sort size used in the recursive calls by rounding the 2/3 upwards, e.g. rounding 2/3 of 5 should give 4 rather than 3, as otherwise the sort can fail on certain data.