Branches - Brianna

lib/tree.rb

@@ -1,66 +1,145 @@
 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
   attr_reader :root
   def initialize
     @root = nil
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def add_helper(current_node, key, value)
+    return TreeNode.new(key, value) if current_node.nil?
+
+    if key < current_node.key
+      current_node.left = add_helper(current_node.left, key, value)
+    else
+      current_node.right = add_helper(current_node.right, key, value)
+    end
+
+    return current_node
+  end
+
+  # Time Complexity: O(log n)
+  # Space Complexity: O(log n)
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value)
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def find_helper(current_node, target)
+    return current_node if current_node == nil
+    return current_node.value if current_node.key == target
+
+    if target < current_node.key
+      find_helper(current_node.left, target)
+    else
+      find_helper(current_node.right, target)
+    end
+
+  end
+
+  # Time Complexity: O(log n)
+  # Space Complexity: O(log n)
   def find(key)
-    raise NotImplementedError
+    return find_helper(@root, key)
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def inorder_helper(current_node, list)
+    return list if current_node.nil?
+
+    inorder_helper(current_node.left, list)
+    list << {key: current_node.key, value: current_node.value}
+    inorder_helper(current_node.right, list)
+
+    return list
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def inorder
-    raise NotImplementedError
+    return inorder_helper(@root, [])
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def preorder_helper(current_node, list)
+    return list if current_node.nil?
+
+    list << {key: current_node.key, value: current_node.value}
+    preorder_helper(current_node.left, list)
+    preorder_helper(current_node.right, list)
+
+    return list
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def preorder
-    raise NotImplementedError
+    return preorder_helper(@root, [])
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  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 << {key: current_node.key, value: current_node.value}
+
+    return list
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def postorder
-    raise NotImplementedError
+    return postorder_helper(@root, [])
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  # Time Complexity: O(log n)
+  # Space Complexity: O(log n)
+
+  def height_helper(current_node)
+    return 0 if current_node.nil?
+
+    left = height_helper(current_node.left)
+    right = height_helper(current_node.right)
+
+    if left > right
+      return left += 1
+    else
+      return right += 1
+    end
+  end
+
   def height
-    raise NotImplementedError
+    return 0 if @root.nil?
+    return height_helper(@root)
   end
-
+  
   # Optional Method
   # Time Complexity: 
   # Space Complexity: 
   def bfs
     raise NotImplementedError
   end
-
+  
   # Useful for printing
   def to_s
     return "#{self.inorder}"
   end
 end
+
+# tree = Tree.new
+# tree.add(1, "Brianna")
+# tree.add(2, "Brianna")
+# tree.add(3, "Brianna")
+# # p tree
+
+# # p tree.inorder
+# p tree.find(2)
+# p tree.find(3)