Liv - Space

lib/tree.rb

@@ -16,40 +16,47 @@ def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: o(logn)
+  # Space Complexity: o(logn)
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: o(logn)
+  # Space Complexity: o(logn)
   def find(key)
-    raise NotImplementedError
+    current = @root
+    return nil if current.nil?
+
+    until current.key == key
+      (current.key > key) ? (current = current.left) : (current = current.right)
+    end
+
+    return current.value
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: on
+  # Space Complexity: on
   def inorder
-    raise NotImplementedError
+    return inorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: on
+  # Space Complexity: on
   def preorder
-    raise NotImplementedError
+    preorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: on
+  # Space Complexity: on
   def postorder
-    raise NotImplementedError
+    postorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: on
+  # Space Complexity: on
   def height
-    raise NotImplementedError
+    return height_helper(@root)
   end
 
   # Optional Method
@@ -63,4 +70,58 @@ def bfs
   def to_s
     return "#{self.inorder}"
   end
+
+
+  ##HELPERS
+
+  def add_helper(node, key, value)
+    return TreeNode.new(key, value) if node.nil?
+
+    if key < node.key
+      node.left = add_helper(node.left, key, value)
+    else
+      node.right = add_helper(node.right, key, value)
+    end
+
+    return node
+  end
+
+  def inorder_helper(current, list)
+    return list if current.nil?
+
+    inorder_helper(current.left, list)
+    list << { key: current.key, value: current.value}
+    inorder_helper(current.right, list)
+
+    return list
+  end
+
+  def preorder_helper(current, list)
+    return list if current.nil?
+
+    list << {key: current.key, value: current.value}
+    preorder_helper(current.left, list)
+    preorder_helper(current.right, list)
+
+    return list
+  end
+
+  def postorder_helper(current, list)
+    return list if current.nil?
+
+    postorder_helper(current.left, list)
+    postorder_helper(current.right, list)
+    list << {key: current.key, value: current.value}
+
+    return list
+  end
+
+  def height_helper(current)
+    return 0 if current.nil?
+
+    left = height_helper(current.left)
+    right = height_helper(current.right)
+
+    left > right ? (left + 1) : (right + 1)
+  end
 end