From bf01312f97be61b75fcb36a45eb06df32be02f8b Mon Sep 17 00:00:00 2001
From: Alice Boone <alicegbonel@gmail.com>
Date: Sat, 10 Apr 2021 13:57:23 -0700
Subject: [PATCH 1/3] add and find methods

---
 lib/tree.rb | 65 +++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 46 insertions(+), 19 deletions(-)

diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..e8b252a 100644
--- a/lib/tree.rb
+++ b/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
@@ -16,51 +16,78 @@ def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log n)
+  # Space Complexity: O(1)
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value)
+  end
+
+  def add_helper(root, key, value)
+    if root.nil?
+      root = TreeNode.new(key, value)
+      return root
+    end
+
+    if root.key > key
+      root.left = add_helper(root.left, key, value)
+    else
+      root.right = add_helper(root.right, key, value)
+    end
+
+    root
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(log n)
+  # Space Complexity: O(log n)
   def find(key)
-    raise NotImplementedError
+    find_helper(@root, key)
+  end
+
+  def find_helper(node, key)
+    return nil if node.nil?
+
+    if node.key == key
+      node.value
+    elsif node.key < key
+      find_helper(node.right, key)
+    else
+      find_helper(node.left, key)
+    end
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def inorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def preorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def postorder
     raise NotImplementedError
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def height
     raise NotImplementedError
   end
 
   # Optional Method
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity:
+  # Space Complexity:
   def bfs
     raise NotImplementedError
   end
 
   # Useful for printing
   def to_s
-    return "#{self.inorder}"
+    inorder.to_s
   end
 end

From 4e2bda8506409958f497445acdc9b449af27f069 Mon Sep 17 00:00:00 2001
From: Alice Boone <alicegbonel@gmail.com>
Date: Sat, 10 Apr 2021 14:55:01 -0700
Subject: [PATCH 2/3] inorder, preorder, postorder  methods

---
 lib/tree.rb | 48 +++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/lib/tree.rb b/lib/tree.rb
index e8b252a..9e2daaa 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -55,22 +55,52 @@ def find_helper(node, key)
     end
   end
 
-  # Time Complexity:
-  # Space Complexity:
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def inorder
-    raise NotImplementedError
+    result = []
+    inorder_helper(@root, result)
+    result
   end
 
-  # Time Complexity:
-  # Space Complexity:
+  def inorder_helper(node, result)
+    return if node.nil?
+
+    inorder_helper(node.left, result)
+    result.push({ key: node.key, value: node.value })
+    inorder_helper(node.right, result)
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def preorder
-    raise NotImplementedError
+    result = []
+    preorder_helper(@root, result)
+    result
   end
 
-  # Time Complexity:
-  # Space Complexity:
+  def preorder_helper(node, result)
+    return if node.nil?
+
+    result.push({ key: node.key, value: node.value })
+    preorder_helper(node.left, result)
+    preorder_helper(node.right, result)
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def postorder
-    raise NotImplementedError
+    result = []
+    postorder_helper(@root, result)
+    result
+  end
+
+  def postorder_helper(node, result)
+    return if node.nil?
+
+    postorder_helper(node.left, result)
+    postorder_helper(node.right, result)
+    result.push({ key: node.key, value: node.value })
   end
 
   # Time Complexity:

From 07da083181e81d9071d02855b81040b8b92c1481 Mon Sep 17 00:00:00 2001
From: Alice Boone <alicegbonel@gmail.com>
Date: Sat, 10 Apr 2021 14:57:20 -0700
Subject: [PATCH 3/3] height  method

---
 lib/tree.rb | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/tree.rb b/lib/tree.rb
index 9e2daaa..6179324 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -103,17 +103,23 @@ def postorder_helper(node, result)
     result.push({ key: node.key, value: node.value })
   end
 
-  # Time Complexity:
-  # Space Complexity:
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def height
-    raise NotImplementedError
+    height_helper(@root, 0)
+  end
+
+  def height_helper(node, steps)
+    return steps if node.nil?
+
+    [height_helper(node.left, steps + 1), height_helper(node.right, steps + 1)].max
   end
 
   # Optional Method
   # Time Complexity:
   # Space Complexity:
   def bfs
-    raise NotImplementedError
+    return [] if @root.nil?
   end
 
   # Useful for printing