100 prisoners problem
I'm confused...<p>"Before the first prisoner enters the room, the prisoners may discuss strategy—but may not communicate once the first prisoner enters to look in the drawers."<p>And, in the example given, "That prisoners 5 to 8 will also find their numbers can also be derived from the information gained by the first three prisoners."<p>There's never any explanation of what happens when a prisoner opens a drawer and finds it empty. In the first example given, what happens when prisoner 5 goes in and there's nothing in drawer 5? The algorithm doesn't seem to account for this.<p>It seems like there's some sort of assumption that the later prisoners are gathering information from the earlier prisoners, but the problem set-up seems to preclude this? They're going into a room so they can't watch each other, the drawers are closed afterwards so they can't derive information from which drawers are open/closed, and they're not allowed to communicate.<p>Am I not following something?