Implement balanced binary tree and refactor

[tiger.ml.git] / exercises / ch01 / tree.ml

diff --git a/exercises/ch01/tree.ml b/exercises/ch01/tree.ml
index 7cc7d8c..521b6cf 100644 (file)
--- a/exercises/ch01/tree.ml
+++ b/exercises/ch01/tree.ml
@@ -1,42 +1,13 @@
-module Array = ArrayLabels
+module type S = sig
+  type ('k, 'v) t
 
-module type TREE = sig
-  type 'a t
+  val empty : ('k, 'v) t
 
-  val empty : 'a t
+  val set : ('k, 'v) t -> k:'k -> v:'v -> ('k, 'v) t
 
-  val add : 'a t -> 'a -> 'a t
+  val get : ('k, 'v) t -> k:'k -> 'v option
 
-  val member : 'a t -> 'a -> bool
-end
-
-module BinaryTree : TREE = struct
-  type 'a t =
-    | Node of 'a * 'a t * 'a t
-    | Leaf
-
-  let empty = Leaf
+  val member : ('k, 'v) t -> k:'k -> bool
 
-  let rec add t x =
-    match t with
-    | Leaf -> Node (x, Leaf, Leaf)
-    | Node (x', left, right) when x < x' -> Node (x', add left x, right)
-    | Node (x', left, right) when x > x' -> Node (x', left, add right x)
-    | (Node _) as t' -> t'
-
-  let rec member t x =
-    match t with
-    | Leaf -> false
-    | Node (x', left, _) when x < x' -> member left x
-    | Node (x', _, right) when x > x' -> member right x
-    | Node _ -> true
+  val to_dot : ('k, 'v) t -> k_to_string:('k -> string) -> string
 end
-
-let () =
-  let tree =
-    Array.fold_left
-      (Sys.argv)
-      ~init:BinaryTree.empty
-      ~f:(fun t str -> BinaryTree.add t str)
-  in
-  Printf.printf "%B\n" (BinaryTree.member tree "a")