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From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject: Re: Sudoku solver
Date: Thu, 26 Mar 2015 20:42:32 -0400
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On Thu, 26 Mar 2015 23:37:10 +1100, Chris Angelico <rosuav@gmail.com>
declaimed the following:

>
>Nothing. And solving a Sudoku puzzle - or any other puzzle - should
>require no guessing. It should be possible to solve purely by logic.
>Same goes for every other kind of puzzle out there; it's highly
>unsatisfying to play Minesweeper and get to the end with a block of
>four squares in a corner, two mines left, and no way of knowing which
>diagonal has the mines and which is clear.
>
	I've encountered (a few years ago, when Sudoku became popular) some
puzzles in books that were like your Minesweeper example.

	The difference being that either "diagonal" produced a valid solution,
whereas Minesweeper was "ask the Fates to be kind" (and the reason the
original M$ Minesweeper never "died" on the first move -- the mines weren't
placed until the player made the first choice).


	These were Sudoku puzzles where the last four empty cells formed a
square, such that putting X on one diagonal and Y on the other diagonal
formed a valid solution... But so did swapping the X/Y diagonals.
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/