Earth/Taylor

lib/tree.rb

@@ -1,3 +1,5 @@
+require_relative '../../stacks-queues/lib/queue'
+
 class TreeNode
   attr_reader :key, :value
   attr_accessor :left, :right
@@ -11,52 +13,112 @@ def initialize(key, val)
 end
 
 class Tree
-  attr_reader :root
+  attr_reader :root, :size
   def initialize
     @root = nil
+    @size = 0
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
   def add(key, value)
-    raise NotImplementedError
+    if @root.nil?
+      @root = TreeNode.new(key, value)
+    else
+      current = @root
+      prev = @root
+
+      while current
+        prev = current
+        if key < current.key
+          current = current.left
+        else
+          current = current.right
+        end
+      end
+      if key < prev.key
+        prev.left = TreeNode.new(key, value)
+      else
+        prev.right = TreeNode.new(key, value)
+      end
+    end
+    @size += 1
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: worst case: O(n), best case: O(log n)
+  # Space Complexity: O(1)
   def find(key)
-    raise NotImplementedError
+    current = @root
+    while current
+      if current.key == key
+        return current.value
+      elsif key > current.key
+        current = current.right
+      else
+        current = current.left
+      end
+    end
+    return nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def inorder
-    raise NotImplementedError
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def inorder(array=[], current=@root)
+    return array if current == nil
+    inorder(array, current.left)
+    array << {key: current.key, value: current.value}
+    inorder(array, current.right)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def preorder
-    raise NotImplementedError
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def preorder(array=[],current=@root)
+    return array if current.nil?
+    array << {key: current.key, value: current.value}
+    preorder(array, current.left)
+    preorder(array, current.right)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def postorder
-    raise NotImplementedError
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def postorder(array=[], current=@root)
+    return array if current.nil?
+    postorder(array, current.left)
+    postorder(array, current.right)
+    array << {key: current.key, value: current.value}
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def height
-    raise NotImplementedError
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
+  def height(current=@root)
+    return 0 if current.nil?
+    return 1 if current.right.nil? && current.left.nil?
+
+    left_count = 0
+    right_count = 0
+    left_count += 1 + height(current.left)
+    right_count += 1 + height(current.right)
+    left_count > right_count ? left_count : right_count
   end
 
   # Optional Method
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def bfs
-    raise NotImplementedError
+    array = []
+    return array if @root.nil?
+    queue = [@root]
+    while !queue.empty?
+      current = queue.shift
+      array << {key: current.key, value: current.value}
+      unless current.left.nil?
+        queue.push(current.left)
+      end
+      unless current.right.nil?
+        queue.push(current.right)
+      end
+    end
+    return array
   end
 
   # Useful for printing

test/tree_test.rb

@@ -91,7 +91,7 @@
     it "will return 1 for a tree of height 1" do
       my_tree = Tree.new
 
-      my_tree.add(100)
+      my_tree.add(100, "bruno")
       expect(my_tree.height).must_equal 1
     end
 
@@ -102,23 +102,23 @@
     it "will report the height for unbalanced trees" do
       my_tree = Tree.new
 
-      my_tree.add(100)
-      my_tree.add(110)
-      my_tree.add(120)
-      my_tree.add(130)
-      my_tree.add(140)
+      my_tree.add(100, "bella")
+      my_tree.add(110, "rocky")
+      my_tree.add(120, "snowball")
+      my_tree.add(130, "mr. whiskers")
+      my_tree.add(140, "bebe")
 
       expect(my_tree.height).must_equal 5
 
       my_tree = Tree.new
 
       my_tree = Tree.new
 
-      my_tree.add(100)
-      my_tree.add(90)
-      my_tree.add(80)
-      my_tree.add(70)
-      my_tree.add(60)
+      my_tree.add(100, "bruno")
+      my_tree.add(90, "bella")
+      my_tree.add(80, "arbor")
+      my_tree.add(70, "teal")
+      my_tree.add(60, "josh")
 
       expect(my_tree.height).must_equal 5
     end