Lance Walton lancewalton
lancewalton
/ Chess
Created
August 31, 2013 21:14
Two solutions to the problem of finding all placements of some collection of chess pieces on a chess board of specified size such that no piece is under threat from any other. The problem was recently posed to me by a friend. The 'optimised' solution is significantly faster that the 'unoptimised' one. For example, on my laptop, the n-queens prob…
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| package chess | |
| // Everything from this line down to the cut is common to the 'unoptimised' and 'optimised' solutions | |
| case class Location(row: Int, column: Int) | |
| trait Piece { | |
| def canAttackLocation(from: Location, to: Location): Boolean | |
| } | |
| case object Rook extends Piece { |
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| package sudoku | |
| case class Location(row: Int, col: Int) { | |
| def areValuesMutuallyExclusive(other: Location, size: Int) = | |
| isInSameRow(other) || | |
| isInSameColumn(other) || | |
| isInSameSmallSquare(other, size) | |
| private def isInSameRow(other: Location): Boolean = row == other.row |
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