start with three

.gitignore

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+!*.hs

three.hs

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+
+splitlist :: [a] -> ([a],[a])
+splitlist list = (take n list,drop n list)
+  where n = (length list) `div` 2
+
+inBoth :: (Eq a) => ([a],[a]) -> [a]
+inBoth (first,second) = do
+  inFirst <- first
+  if (inFirst `elem` second) then return inFirst else []
+
+
+
+main = do
+  input <- readFile "three-input.txt"
+  print $ map ( inBoth . splitlist ) $ lines input