Picking A Pivot

What kind of pivot do we want to pick?

• Max or min? No, then we get selection sort because one list will have n-1 elements and the other 0.
• First element in list? Not good if list sorted or reverse sorted (get max or min)!
• Median of list? That would be perfect... T(n) = n = 2 T(n/2). Hard to find quickly. (Can be done in linear time, however.)
• Random element in list? Good chance of breaking the list into substantial chunks. Fast. But random... more complex analysis. (Next time.)
• Median of 3 randoms? More work, but more stable.