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: Solution based on the OSort sorting algorithm by Charlie)
Ack! You're absolutely correct.
The OSort is different from the shell sort in a cuople of ways. the shell sort starts with a step size of 3 where the OSort starts with a step size of n/21, and the shell sort decrements the step by 1 whereas the OSort's step size decrements by some factor between .78 and .86, depending on which version.
I never tested the OSort on a sample size this small before.

Posted by Erik
on 20040602 13:11:05 