You have five coins, apparently alike, but actually of different weights. You also have a two arm scale.

Can you manage to sort the coins in ascending order, using the scale only seven times?

Bonus question: can it be done in fewer weighings?

(In reply to re(6): Solution based on the O-Sort sorting algorithm by Erik O.)

Your link has a missing / between computer and sortroutines (in the visible verions it has a backslash there, but in the actual link there's nothing there).

I did find that even .81 failed to sort completely, so I doubt .78 would work either.

Of course one could guarantee that it would work if when it reached the step-1 level, that if it found it necessary to swap anything it would go through the step-1 level again, and so on until no swaps were made.

Posted by Charlie on 2004-06-03 22:38:11