Add "Crack the Coding Interview" examples

I believe I have multiple other snippets and attempts scattered across /tmp,
~/programming, and other directories. Again, I created these files and others
before the mono-repo.

crack_the_coding_interview/to_tree.hs

@@ -0,0 +1,11 @@
+data Tree a = Node a [Tree a] deriving (Show)
+
+withRoot :: [a] -> [Tree a]
+withRoot xs = xs |> toThing |> fmap buildTree
+
+buildTree :: (a, [a])
+
+
+toTree :: [a] -> Tree a
+toTree [x]      = Node x []
+toTree [x | xs] = Node x (toTree xs)