22 lines
629 B
Haskell
22 lines
629 B
Haskell
module Dodge.Graph
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where
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import Data.Function (on)
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import Data.List
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import Data.Graph
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pairsToIncidence :: (Eq a,Ord a) => [(a,a)] -> [(a,[a])]
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pairsToIncidence = map ((\(xs,ys) -> (head xs,ys)) . unzip)
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. groupBy ( (==) `on` fst)
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. sort
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incidenceToFunction :: Eq a => [(a,[a])] -> a -> [a]
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incidenceToFunction xs a = case lookup a xs of Just ys -> ys
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Nothing -> []
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mkNode :: (a,[a]) -> (a,a,[a])
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mkNode (x,xs) = (x,x,xs)
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pairsToSCC :: (Eq a, Ord a) => [(a,a)] -> [SCC a]
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pairsToSCC = stronglyConnComp . map mkNode . pairsToIncidence
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