binary_search_tree

elixir/binary-search-tree/lib/binary_search_tree.ex

@@ -0,0 +1,26 @@
+defmodule BinarySearchTree do
+  @type bst_node :: %{data: any, left: bst_node | nil, right: bst_node | nil}
+
+  @doc """
+  Create a new Binary Search Tree with root's value as the given 'data'
+  """
+  @spec new(any) :: bst_node
+  def new(data), do: %{data: data, left: nil, right: nil}
+
+  @doc """
+  Creates and inserts a node with its value as 'data' into the tree.
+  """
+  @spec insert(bst_node, any) :: bst_node
+  def insert(nil, data), do: new(data)
+  def insert(tree, data) when data <= tree.data, do:
+    %{tree | left: insert(tree.left, data)}
+  def insert(tree, data), do:
+    %{tree | right: insert(tree.right, data)}
+
+  @doc """
+  Traverses the Binary Search Tree in order and returns a list of each node's data.
+  """
+  @spec in_order(bst_node) :: [any]
+  def in_order(nil), do: []
+  def in_order(tree), do: in_order(tree.left) ++ [tree.data | in_order(tree.right)]
+end