Adding Haskell examples (#17)

* Adding binary search example for Haskell

* Adding selection sort example in Haskell

* Adding Haskell examples for chapter 3

* Adding examples for chapter 4

* Adding examples for chapter 5

* Adding git ignore

* Add Haskell example for BFS

04_quicksort/Haskell/01_02_loop_sum.hs

@@ -0,0 +1,5 @@
+
+sumarr [] = 0
+sumarr (x: xs) = x + sumarr xs
+
+main = putStrLn (show (sumarr [1,2,3,4]))

04_quicksort/Haskell/03_recursive_count.hs

@@ -0,0 +1,5 @@
+
+countarr [] = 0
+countarr (x:xs) = 1 + countarr xs
+
+main = (putStrLn . show . countarr) [0, 1, 2, 3, 4, 5]

04_quicksort/Haskell/04_recursive_max.hs

@@ -0,0 +1,6 @@
+
+maxarr (x: []) = x
+maxarr (x:xs) = if x > maxofrest then x else maxofrest
+  where maxofrest = maxarr xs
+
+main = (putStrLn . show . maxarr) [1, 5, 10, 25, 16, 1]

04_quicksort/Haskell/05_quicksort.hs

@@ -0,0 +1,8 @@
+import Data.List
+
+quicksort [] = []
+quicksort (x: []) = [x]
+quicksort (x:xs) = (quicksort lessthan) ++ [x] ++ (quicksort greaterthan)
+  where (lessthan, greaterthan) = partition (<= x) xs
+
+main = (putStrLn . show . quicksort) [0,9,4,5,6,3,1,0,1]