[pmiller2]

Nitpick: \rho = n/2 in the worst case, if n > 1, but that still gives you O(n log n).

[Fri31Aug]

Why n/2? If the array is, for example, sorted in the reverse order, then there is no monotonous run at all, in which case I believe the algorithm considers each element from the array being a run in itself, giving n runs.

[pxndx]

Runs can be increasing or decreasing, a reversed array is a single run. Worst case is n/2 because you can always split the array in pairs (if it alternates a high and a low value for example).

[Fri31Aug]

Ah I didn't know it also exploited reversed runs. Amazing.