[net.puzzle] tall and short cannibals

rainbow@ihuxe.UUCP (11/09/84)

Newsgroups: net.puzzle
Subject: Figure me this...

You are shipwrecked and wash ashore onto an island populated by
cannibals. There are two types of cannibals on this island:
short ones who always tell the truth and tall ones who always lie.

As you crawl up the beach, one of the short ones, the chief, 
approaches you and makes you an offer you can't refuse.

The chief blindfolds you and places three men from his tribe
near you on the beach. From what they say to you, you must
tell the chief which are short and which are tall - and prove
your answer. If you manage to do this, you will be set free.
Otherwise, you are invited to dinner.

As the first tribesman begins to speak, a wave breaks on the
nearby reef and drowns out his voice.  Then you hear the 
second say 'The first one said he is short and he is, and so
am I". The third one says 'The second one is lying, he is 
tall and I am short'. 

> Well, the second must be telling the truth. Whether a cannibal is tall
> or short, he will say he his short.
> Hence, the third must be lying when he claims the second speaks with
> forked tongue.
> It follows directly: First is short, Second is short, third is tall.
>
> Robert