urn:lj:livejournal.com:atom1:zunger Yonatan Zunger Yonatan Zunger 2010-04-30T18:21:42Z urn:lj:livejournal.com:atom1:zunger:168060 2010-04-30T17:39:39Z 2010-04-30T18:21:42Z So a few days ago, I got an amusing idea for an interview question which I realized was totally pointless as an interview question, because it has no practical value whatsoever. So instead, I'm going to post it on my blog, as a way to help waste the time of all my CS friends. There is no prize whatsoever for a correct answer, except for the satisfaction of having <s>avoided work for a while</s> solved an amusing problem.<br /><br />Here are two really bad ways to sort an array:<br /><ol><li>Random sort: Repeatedly select a random permutation and apply it to the set. Stop when it becomes sorted.</li><br /><li>Brute-force sort: Iterate over the set of all permutations of N elements. Apply each in turn. If the list is now sorted, stop.</li></ol><br />The question is: which of the two is less efficient, and (the trickier part) by how much?<br /><br />(Clarification: For the latter, "how much" in terms of average [mean] time to sort. You can also average over a large number of possible inputs)