Space - Stephanie

lib/tree.rb

@@ -2,12 +2,12 @@ class TreeNode
   attr_reader :key, :value
   attr_accessor :left, :right
 
-   def initialize(key, val)
+  def initialize(key, val)
     @key = key
     @value = val
     @left = nil
     @right = nil
-   end
+  end
 end
 
 class Tree
@@ -19,44 +19,119 @@ def initialize
   # Time Complexity: 
   # Space Complexity: 
   def add(key, value)
-    raise NotImplementedError
+    new_node = TreeNode.new(key, value)
+    @root.nil? ? @root = new_node : comparative_helper(@root, new_node)
+  end
+
+  def comparative_helper(current_node, new_node)
+    return new_node if current_node.nil?
+
+    if new_node.key <= current_node.key
+      current_node.left = comparative_helper(current_node.left, new_node)
+    else
+      current_node.right = comparative_helper(current_node.right, new_node)
+    end
+
+    return current_node
   end
 
   # Time Complexity: 
   # Space Complexity: 
   def find(key)
-    raise NotImplementedError
+    return nil if @root.nil?
+    return @root.value if @root.key == key
+
+    current_node = @root
+
+    until current_node == nil 
+      return current_node.value if key == current_node.key
+      current_node = current_node.left if key < current_node.key
+      current_node = current_node.right if key > current_node.key
+    end 
+
   end
 
   # Time Complexity: 
   # Space Complexity: 
   def inorder
-    raise NotImplementedError
+    return [] if @root.nil?
+    ordered_list = []
+    holder = []
+    current_node = @root
+
+    while !current_node.nil? || !holder.empty?
+      until current_node.nil? 
+        holder << current_node
+        current_node = current_node.left 
+      end
+
+      current_node = holder.pop
+      list_pusher(current_node, ordered_list)
+      current_node = current_node.right 
+    end
+
+    return ordered_list
+
   end
 
   # Time Complexity: 
   # Space Complexity: 
   def preorder
-    raise NotImplementedError
+    return [] if @root.nil?
+    return preorder_helper(@root, [])
+  end
+
+  def preorder_helper(current_node, list)
+    return list if current_node.nil?
+
+    list_pusher(current_node, list)
+    preorder_helper(current_node.left, list)
+    preorder_helper(current_node.right, list)
+
+    return list
   end
 
   # Time Complexity: 
   # Space Complexity: 
   def postorder
-    raise NotImplementedError
+    return [] if @root.nil?
+    postorder_helper(@root, [])
+  end
+
+  def postorder_helper(current_node, list)
+    return list if current_node.nil?
+
+    postorder_helper(current_node.left, list)
+    postorder_helper(current_node.right, list)
+    list_pusher(current_node, list)
+
+    return list
+  end
+
+  def list_pusher(current_node, list)
+    list << {key: current_node.key, value: current_node.value}
   end
 
   # Time Complexity: 
   # Space Complexity: 
   def height
-    raise NotImplementedError
+    return 0 if @root.nil? 
+    height_helper(@root)
+  end
+
+  def height_helper(current_node)
+    return 0 if current_node.nil? 
+    left = height_helper(current_node.left)
+    right = height_helper(current_node.right)
+    left > right ? (return left + 1) : (return right + 1)
   end
 
+
   # Optional Method
   # Time Complexity: 
   # Space Complexity: 
   def bfs
-    raise NotImplementedError
+
   end
 
   # Useful for printing