From: Ruby Quiz <james@...>
Date: 2005-04-09T03:38:08+09:00
Subject: [QUIZ] Knight's Travails (#27)

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by Jason Bailey

Given a standard 8 x 8 chessboard where each position is indicated in algebraic
notation (with the lower left corner being a1), design a script that accepts two
or more arguments.

The first argument indicates the starting position of the knight.  The second
argument indicates the ending position of the knight.  Any additional arguments
indicate positions that are forbidden to the knight.

Return an array indicating the shortest path that the knight must travel to get
to the end position without landing on one of the forbidden squares. If there is
no valid path to the destination return nil.

	example 1:
	a8, b7, b6
	
	could return
	[ c7 , b5 , d6 , b7 ]
	
	Example 2:
	a8 , g6 , b6 , c7
	
	would return
	nil

Note: That in the majority of cases it would be possible to have more then one
valid path.