Newsgroups: comp.ai.games
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From: Ka Lam <g5kalam@cdf.toronto.edu>
Subject: eight puzzle decission question
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Date: Sun, 23 Jun 1996 18:43:44 GMT
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I have the following question:

	In an eight-puzzle game, define as following:

	start				goal

	2 8 3				1 2 3
	1 6 4				8 b 4
	7 b 5				7 6 5

	The purpose of the game is silding the B tile until start from
start until I reach the goal.  (this is also known as the sliding puzzle
game).

	I have to write a LISP program to do this. (in other words, AI! )
I have successed is writing the part that solve the problem.  But, in this
game, there are pairs of start and goal state, which has no way of
reaching.  

	Example:

	1 2 3 			1 2 3
	4 5 6			4 5 6
	7 8 b			8 7 b

	My question is, how do I check of these "pairs"?  I heard that
there is an easy, and quick way of checking, but I can't come up with
it. 

	Thanks for any help.

ps. please reply by email and posting.  Because I am in a hurry to find
the solution.

--
University of Toronto                  g5kalam@cdf.utoronto.ca
Art & Science                          ae197@freenet.toronto.on.ca
Ka Lam                      Home Page: http://cdf.utoronto.ca/~g5kalam
   Administrator of Methodist (H.K.) Primary & College Mailing-List
    Vice President of UoT Computer Science Student Union, 1996/97

