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From: root@kunivv1.sci.kun.nl (Privileged Account)
Newsgroups: comp.misc
Subject: Re: Tic-Tac-Toe algorithm?
Message-ID: <1635@kunivv1.sci.kun.nl>
Date: 4 Jun 90 12:08:45 GMT
References: <13742@venera.isi.edu>
Organization: University of Nijmegen, The Netherlands
Lines: 26

In article <13742@venera.isi.edu> lpress@venera.isi.edu (Laurence I. Press) writes:
>I recall seeing a very simple algorithm for playing optimal tic-tac-toe
>which was based on merely doing arithmetic on the values of the cells
>when arranged as follows:
>
>1 2 3
>4 5 6
>7 8 9
>
>Does anyone know what the trick is (I can't remember)?
>
>Lar

I think you are referring to this little game in which the players
alternately mention numbers in the range 1..9 until one of them has
mentioned three numbers whose sum is 15.  This game is essentially
equivalent to playing tic-tac-toe on a board that looks like:

8 3 4
1 5 9
6 7 2

Or is there more to it?

--
Hans Mulder		hansm@cs.kun.nl