use Perl

• Solution (Score:2)

  by davorg (18)

  You ask either one of the lions which door the _other_ lion would say is the right door. The answer you get is guaranteed to be the wrong door so you choose the other one.
  
  It's a very old and well-known puzzle.
  
• 3 Person Variation (Score:1)

  by Limbic Region (3985)

  The one you stated is a well known version. While I was in Germany on business, I found a variation
  
  There are 3 people - 1 always lies, 1 always tells the truth, and one randomly lies tells truth
  
  You can ask two questions this time - both to the same person or to different people - still only two paths/doors though
  
  The questions can't be compound (if this and this) - must be yes/no type questions - and can't create paradoxes
  
  Now I stayed up all night and came up with a solution - submitted it to the author
• If you like this sort of puzzle (Score:1)

  by VSarkiss (704)

  Sometimes these are called knights-and-knaves puzzles (knights always tell the truth, knaves always lie). If you like them, you should really read some of Raymond Smullyan's [wikipedia.org] books. He's come up with tons and tons of interesting variations.

  My favorite puzzle book of his is "What Is the Name of This Book?", although I haven't read some of his newer ones.