to make qsort more robust:
* use "ninther" to choose pivot.
* use three-way partition to avoid quadratic
behavior on all-one-value arrays.
also add tests suggested in that paper.
the immediate cause of the slowness we observed was
in fact none of these: the recursive call was sorting
data[0:m] instead of data[a:m].
also rename package to "sort" to match convention.
R=r,gri
DELTA=358 (255 added, 21 deleted, 82 changed)
OCL=19341
CL=19373
(work now with Ken's latest compiler fix)
- exoanded test cases accordingly
- fixed a type in the spec (thx r)
R=r
DELTA=65 (62 added, 2 deleted, 1 changed)
OCL=15050
CL=15050
