15 lines
468 B
Haskell
15 lines
468 B
Haskell
import Data.List
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import qualified Data.Set as Set
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data Piece = K | Q | R | B | N deriving (Eq, Ord, Show)
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isChess960 :: [Piece] -> Bool
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isChess960 rank =
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(odd . sum $ findIndices (== B) rank) && king > rookA && king < rookB
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where
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Just king = findIndex (== K) rank
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[rookA, rookB] = findIndices (== R) rank
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main :: IO ()
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main = mapM_ (putStrLn . concatMap show) . Set.toList . Set.fromList
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. filter isChess960 $ permutations [R,N,B,Q,K,B,N,R]
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