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Damm algorithm: Difference between revisions
m
→{{header|Haskell}}
Line 629:
<lang haskell>import Data.Char (ord)
import Text.Printf (printf)
table =▼
[ [0, 3, 1, 7, 5, 9, 8, 6, 4, 2]▼
, [7, 0, 9, 2, 1, 5, 4, 8, 6, 3]▼
, [4, 2, 0, 6, 8, 7, 1, 3, 5, 9]▼
, [1, 7, 5, 0, 9, 8, 3, 4, 2, 6]▼
, [6, 1, 2, 3, 0, 4, 5, 9, 7, 8]▼
, [3, 6, 7, 4, 2, 0, 9, 5, 8, 1]▼
, [5, 8, 6, 9, 7, 2, 0, 1, 3, 4]▼
, [8, 9, 4, 5, 3, 6, 2, 0, 1, 7]▼
, [9, 4, 3, 8, 6, 1, 7, 2, 0, 5]▼
, [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]▼
damm :: String -> Bool
damm = (==0) . foldl (\r n -> table !! r !! (ord n - ord '0')) 0
where
▲ table =
▲ [ [0, 3, 1, 7, 5, 9, 8, 6, 4, 2]
▲ , [7, 0, 9, 2, 1, 5, 4, 8, 6, 3]
▲ , [4, 2, 0, 6, 8, 7, 1, 3, 5, 9]
▲ , [1, 7, 5, 0, 9, 8, 3, 4, 2, 6]
▲ , [6, 1, 2, 3, 0, 4, 5, 9, 7, 8]
▲ , [3, 6, 7, 4, 2, 0, 9, 5, 8, 1]
▲ , [5, 8, 6, 9, 7, 2, 0, 1, 3, 4]
▲ , [8, 9, 4, 5, 3, 6, 2, 0, 1, 7]
▲ , [9, 4, 3, 8, 6, 1, 7, 2, 0, 5]
▲ , [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]
]
main :: IO ()
| |||