interview quick note

Author: cd155

QuickNote.hs

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+{-
+    Quick note for writing Haskell
+-}
+
+
+-- add module
+module QuickNote where
+
+-- create a synonym 
+type Nat = Int
+
+-- declaration
+mergeSort :: Ord a => [a] -> [a]
+
+-- patten match
+mergeSort [] = []
+mergeSort [x] = [x]
+mergeSort xs = merge (mergeSort firstHalf) (mergeSort secondHalf)
+
+    -- where cause
+    where (firstHalf, secondHalf) = splitAt (length xs `div` 2) xs
+
+merge :: Ord a => [a] -> [a] -> [a]
+merge [] ys = ys
+merge xs [] = xs
+
+-- pattern match for list
+merge (x:xs) (y:ys)
+
+    -- condition statement
+    | x <= y = x : merge xs (y:ys)
+    | otherwise = y : merge (x:xs) ys
+
+-- initialize a list
+smArrX = [1, 4, 10, 100, 1000]
+
+-- ADT (abstract data type) for binary tree
+data BiTree a = Null | Node a (BiTree a) (BiTree a) deriving Show