Posted April 22, 2012
The 100th guy at the end of the line needs to be instructed to say blue if there is an odd number of blue hats in front of him, and red if there is an even number of blue hats.
All the individuals in front of him will be able to deduce their own hat by counting the number of blue hats in front of himself.
All the individuals in front of him will be able to deduce their own hat by counting the number of blue hats in front of himself.