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md2perpe/findSum.hs

Created August 20, 2011 18:44
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findSum.hs
import Data.List(find)
findSum :: Num a => a -> [a] -> Bool
findSum s ns = find (sumIs s) (pairs ns)
where
sumIs :: Num a => a -> (a, a) -> Bool
sumIs s (x, y) = x+y == s
pairs :: [a] -> [(a, a)]
pairs [] = []
pairs' (x:xs) = map (\y->(x,y)) xs ++ pairs xs
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