Leaves - Samantha

lib/tree.rb

@@ -1,64 +1,126 @@
 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: 
+
+  # Time Complexity: O(log n)
+  # Space Complexity: O(1)
+  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 
+
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value)
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  # Time Complexity: O(log n)
+  # Space Complexity: O(1)  
+  def find_helper(current_node, key)
+    return nil if current_node.nil?
+
+    if key > current_node.key 
+      current_node.right = find_helper(current_node.right, key)
+    elsif key < current_node.key
+      current_node.left = find_helper(current_node.left, key)
+    else
+      return current_node.value
+    end
+  end
+
   def find(key)
-    raise NotImplementedError
+    return find_helper(@root, key)
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+  
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)   
   def inorder
-    raise NotImplementedError
+    return inorder_helper(@root, [])
   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 preorder
-    raise NotImplementedError
+    return pre_order_helper(@root, [])
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def pre_order_helper(current_node, list)
+    return list if current_node.nil? 
+
+    list << {key: current_node.key, value: current_node.value}
+    pre_order_helper(current_node.left, list)
+    pre_order_helper(current_node.right, list)
+    return list
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def postorder
-    raise NotImplementedError
+    return post_order_helper(@root, [])
   end
-
-  # Time Complexity: 
-  # Space Complexity: 
+
+  def post_order_helper(current_node, list)
+    return list if current_node.nil? 
+
+    post_order_helper(current_node.left, list)
+    post_order_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 height_helper(current_node)
+    return 0 if current_node.nil?
+
+    if height_helper(current_node.right) > height_helper(current_node.left)
+      return height_helper(current_node.right) + 1
+    else
+      return height_helper(current_node.left) + 1
+    end
+  end 
+
   def height
-    raise NotImplementedError
+    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}"

test/tree_test.rb

@@ -2,121 +2,121 @@
 
 describe Tree do
   let (:tree) {Tree.new}
-
+  
   let (:tree_with_nodes) {
+  tree.add(5, "Peter")
+  tree.add(3, "Paul")
+  tree.add(1, "Mary")
+  tree.add(10, "Karla")
+  tree.add(15, "Ada")
+  tree.add(25, "Kari")
+  tree
+}
+
+describe "add and find" do 
+  it "add & find values" do
     tree.add(5, "Peter")
-    tree.add(3, "Paul")
-    tree.add(1, "Mary")
-    tree.add(10, "Karla")
+    expect(tree.find(5)).must_equal "Peter"
+
     tree.add(15, "Ada")
-    tree.add(25, "Kari")
-    tree
-  }
-
-  describe "add and find" do 
-    it "add & find values" do
-      tree.add(5, "Peter")
-      expect(tree.find(5)).must_equal "Peter"
-
-      tree.add(15, "Ada")
-      expect(tree.find(15)).must_equal "Ada"
-
-      tree.add(3, "Paul")
-      expect(tree.find(3)).must_equal "Paul"
-    end
-
-    it "can't find anything when the tree is empty" do
-      expect(tree.find(50)).must_be_nil
-    end
+    expect(tree.find(15)).must_equal "Ada"
+
+    tree.add(3, "Paul")
+    expect(tree.find(3)).must_equal "Paul"
   end
-
-  describe "inorder" do
-    it "will give an empty array for an empty tree" do
-      expect(tree.inorder).must_equal []
-    end
-
-    it "will return the tree in order" do
-      expect(tree_with_nodes.inorder).must_equal [{:key=>1, :value=>"Mary"}, {:key=>3, :value=>"Paul"}, 
-                                       {:key=>5, :value=>"Peter"}, {:key=>10, :value=>"Karla"}, 
-                                       {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
-    end
+
+  it "can't find anything when the tree is empty" do
+    expect(tree.find(50)).must_be_nil
   end
+end
 
+describe "inorder" do
+  it "will give an empty array for an empty tree" do
+    expect(tree.inorder).must_equal []
+  end
+
+  it "will return the tree in order" do
+    expect(tree_with_nodes.inorder).must_equal [{:key=>1, :value=>"Mary"}, {:key=>3, :value=>"Paul"}, 
+    {:key=>5, :value=>"Peter"}, {:key=>10, :value=>"Karla"}, 
+    {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
+  end
+end
 
-  describe "preorder" do
-    it "will give an empty array for an empty tree" do
-      expect(tree.preorder).must_equal []
-    end
 
-    it "will return the tree in preorder" do
-      expect(tree_with_nodes.preorder).must_equal [{:key=>5, :value=>"Peter"}, {:key=>3, :value=>"Paul"}, 
-                                        {:key=>1, :value=>"Mary"}, {:key=>10, :value=>"Karla"}, 
-                                        {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
-    end
+describe "preorder" do
+  it "will give an empty array for an empty tree" do
+    expect(tree.preorder).must_equal []
   end
+
+  it "will return the tree in preorder" do
+    expect(tree_with_nodes.preorder).must_equal [{:key=>5, :value=>"Peter"}, {:key=>3, :value=>"Paul"}, 
+    {:key=>1, :value=>"Mary"}, {:key=>10, :value=>"Karla"}, 
+    {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
+  end
+end
 
-  describe "postorder" do
-    it "will give an empty array for an empty tree" do
-      expect(tree.postorder).must_equal []
-    end
-
-    it "will return the tree in postorder" do
-      expect(tree_with_nodes.postorder).must_equal [{:key=>1, :value=>"Mary"}, {:key=>3, :value=>"Paul"}, 
-                                         {:key=>25, :value=>"Kari"}, {:key=>15, :value=>"Ada"}, 
-                                         {:key=>10, :value=>"Karla"}, {:key=>5, :value=>"Peter"}]
-    end
+describe "postorder" do
+  it "will give an empty array for an empty tree" do
+    expect(tree.postorder).must_equal []
+  end
+
+  it "will return the tree in postorder" do
+    expect(tree_with_nodes.postorder).must_equal [{:key=>1, :value=>"Mary"}, {:key=>3, :value=>"Paul"}, 
+    {:key=>25, :value=>"Kari"}, {:key=>15, :value=>"Ada"}, 
+    {:key=>10, :value=>"Karla"}, {:key=>5, :value=>"Peter"}]
   end
+end
 
-  describe "breadth first search" do
-    it "will give an empty array for an empty tree" do
-      expect(tree.bfs).must_equal []
-    end
+xdescribe "breadth first search" do
+  it "will give an empty array for an empty tree" do
+    expect(tree.bfs).must_equal []
+  end
+
+  it "will return an array of a level-by-level output of the tree" do
+    expect(tree_with_nodes.bfs).must_equal [{:key=>5, :value=>"Peter"}, {:key=>3, :value=>"Paul"}, 
+    {:key=>10, :value=>"Karla"}, {:key=>1, :value=>"Mary"}, 
+    {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
+  end
+end
 
-    it "will return an array of a level-by-level output of the tree" do
-      expect(tree_with_nodes.bfs).must_equal [{:key=>5, :value=>"Peter"}, {:key=>3, :value=>"Paul"}, 
-                                   {:key=>10, :value=>"Karla"}, {:key=>1, :value=>"Mary"}, 
-                                   {:key=>15, :value=>"Ada"}, {:key=>25, :value=>"Kari"}]
-    end
+describe "height" do 
+  it "will return 0 if tree is empty" do 
+    expect(tree.height()).must_equal 0
   end
 
-  describe "height" do 
-    it "will return 0 if tree is empty" do 
-      expect(tree.height()).must_equal 0
-    end
+  it "will return the nuber of nodes in the longest path" do
+    expect(tree_with_nodes.height).must_equal 4
+    tree_with_nodes.add(60, "sam")
+    tree_with_nodes.add(58, "penny")
+    tree_with_nodes.add(65, "sam")
+    expect(tree_with_nodes.height).must_equal 6
+  end
+
+  it "will give the correct height of a binary search tree" do
+    tree_with_nodes.add(30, "Tatiana")
+    expect(tree_with_nodes.height).must_equal 5
+  end
+end
 
-    it "will return the nuber of nodes in the longest path" do
-      expect(tree_with_nodes.height).must_equal 4
-      tree_with_nodes.add(60, "sam")
-      tree_with_nodes.add(58, "penny")
-      tree_with_nodes.add(65, "sam")
-      expect(tree_with_nodes.height).must_equal 6
-    end
+xdescribe "delete" do
+  it "can delete a note in the tree" do
+    # Arrange & Assert
+    expect(tree_with_nodes.find(15)).must_equal "Ada"
+
+    # Act
+    tree_with_nodes.delete(15)
 
-    it "will give the correct height of a binary search tree" do
-      tree_with_nodes.add(30, "Tatiana")
-      expect(tree_with_nodes.height).must_equal 5
-    end
+    # Assert
+    expect(tree_with_nodes.find(15)).must_be_nil
   end
-
-  describe "delete" do
-    it "can delete a note in the tree" do
-      # Arrange & Assert
-      expect(tree_with_nodes.find(15)).must_equal "Ada"
-
-      # Act
-      tree_with_nodes.delete(15)
-
-      # Assert
-      expect(tree_with_nodes.find(15)).must_be_nil
-    end
-
-    it "will return nil if the node is not in the tree when it's deleted" do
-      # Arrange & Act
-      answer = tree_with_nodes.delete(47)
-
-      # Assert
-      expect(answer).must_be_nil
-      expect(tree_with_nodes.find(47)).must_be_nil
-    end
+
+  it "will return nil if the node is not in the tree when it's deleted" do
+    # Arrange & Act
+    answer = tree_with_nodes.delete(47)
+
+    # Assert
+    expect(answer).must_be_nil
+    expect(tree_with_nodes.find(47)).must_be_nil
   end
 end
+end