Very odd assumption (even somewhat ill-defined).
Stronger (less general, worse) than the assumption in randomized quicksort. There, we showed that the randomization in the algorithm made it so no particular input elicits worst-case behavior.
Weaker (more general, better) than the assumption needed to show non-randomized quicksort efficient. There, we'd need to assume that the probability of a bad input (reversed list) was small.
Here, we are putting a restriction on the combination of our hash function and our inputs. The better our hash function is, the less we care about the key sequence.
