You have three small poles and five hoops - XS, S, M, L, XL (as in extra small, small, medium, large and extra large). They are placed on pole 1 in order, with largest at the bottom.

You can move one hoop at a time, and the hoops you are not moving have to be on a pole. You also cannot place a hoop on top of a smaller one. How can you move the hoops so that they are in the same order as they are now, but on pole 3?

(In reply to A non-recursive solution by Federico Kereki)

In my opinion, this theory is proved by the programs provided in the comments to this problem.

Posted by Xen on 2004-05-25 16:17:04