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| -rw-r--r-- | challenge-124/ulrich-rieke/haskell/ch-2.hs | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/challenge-124/ulrich-rieke/haskell/ch-2.hs b/challenge-124/ulrich-rieke/haskell/ch-2.hs new file mode 100644 index 0000000000..5e79c460c1 --- /dev/null +++ b/challenge-124/ulrich-rieke/haskell/ch-2.hs @@ -0,0 +1,36 @@ +module Challenge124_2 + where +import qualified Data.Set as Set +import Data.List ( minimumBy , sort ) + +combinations :: Int -> [a] -> [[a]] +combinations 0 _ = [[]] +combinations n xs = [ xs !! i : x | i <- [0..(length xs ) - 1 ] , +x <- combinations (n - 1 ) ( drop ( i + 1 ) xs ) ] + +findComplement :: [Int] -> [Int] -> [Int] +findComplement numbers combi = Set.toList ( Set.fromList numbers Set.\\ +Set.fromList combi ) + +solution :: [Int] -> String +solution list = "Subset 1 = " ++ (show $ sort $ fst pair) ++ " " ++ +"Subset 2 = " ++ ( show $ sort $ snd pair ) +where + pair :: ([Int] , [Int] ) + pair = minimumBy myFunc listPairs + l :: Int + l = length list + allCombis :: [[Int]] + allCombis = if even l then combinations ( div l 2 ) list else + (combinations ( div l 2 ) list) ++ ( combinations ( div l 2 + 1 ) list) + listPairs :: [( [Int] , [Int] )] + listPairs = map (\combi -> ( combi , findComplement list combi ) ) + allCombis + myFunc :: ([Int] , [Int] ) -> ([Int] , [Int] ) -> Ordering + myFunc pair1 pair2 + | abs ( (sum $ fst pair1) - (sum $ snd pair1) ) < abs ( (sum $ fst pair2 + ) - (sum $ snd pair2) ) = LT + | abs ( (sum $ fst pair1) - (sum $ snd pair1) ) == abs ( (sum $ fst pair2 + ) - (sum $ snd pair2) ) = EQ + | abs ( (sum $ fst pair1) - (sum $ snd pair1) ) > abs ( (sum $ fst pair2 + ) - (sum $ snd pair2) ) = GT |