From a7b61f0ecd5f2758f6b99c688c120e98af3d1b68 Mon Sep 17 00:00:00 2001
From: "kate.m" <kate.mangubat@highspot.com>
Date: Mon, 31 Aug 2020 09:16:01 -0700
Subject: [PATCH] tree fun

---
 lib/tree.rb | 135 +++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 117 insertions(+), 18 deletions(-)

diff --git a/lib/tree.rb b/lib/tree.rb
index c0d4b51..8e07322 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -16,42 +16,141 @@ def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  
+  #what to do if node is empty, smaller or larger than initial node
+  def add_helper(node, key, value)
+    #if the node is empty, the create the node with a key, value
+    if node.nil?
+      node = TreeNode.new(key, value)
+      #if the key is less than the node key, then put it to the left side
+    elsif key < node.key
+      node.left = add_helper(node.left, key, value)
+      #if key is larger than the node key, then add it to the right side
+    elsif key > node.key
+      node.right = add_helper(node.right, key, value)
+    end
+    return node
+  end
+
+  # Time Complexity: O(1)
+  # Space Complexity: O(1)
   def add(key, value)
-    raise NotImplementedError
+    @root = add_helper(@root, key, value)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+#--------------------------------------------------------------------------#
+#pretty much copied pattern from above
+#what to do if node is empty, return empty
+#otherwise if node is not empty, then set it as the key
+#if key is less than -> left
+#if key is greater than -> right
+def find_helper(node, key)
+  if node.nil?
+    return nil
+  elsif node.key == key
+    return node.value
+  elsif key < node.key
+    return find_helper(node.left, key)
+  elsif key > node.key
+    return find_helper(node.right, key)
+  end
+end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(1)
   def find(key)
-    raise NotImplementedError
+    return find_helper(@root, key)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  #--------------------------------------------------------------------------#
+  #use list is a reference to pass
+  #check if node is empty, if yes, return the list
+  def inorder_helper(node, list) 
+    if node.nil?
+      return list
+    end
+    #push key,value
+    list.push({key: node.key, value: node.value})
+    inorder_helper(node.left, list)
+    inorder_helper(node.right, list)
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def inorder
-    raise NotImplementedError
+    return inorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  #--------------------------------------------------------------------------#
+  #used same logic as inorder
+  #use list is a reference to pass
+  #check if node is empty, if yes, return the list
+  def preorder_helper(node, list) 
+    if node.nil?
+      return list 
+    end
+
+    #push key,value 
+    list.push({key: node.key, value: node.value})
+    preorder_helper(node.left, list)
+    preorder_helper(node.right, list)
+  end
+  
+  
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def preorder
-    raise NotImplementedError
+    return preorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  #--------------------------------------------------------------------------#
+    #used same logic as inorder
+  #use list is a reference to pass
+  #check if node is empty, if yes, return the list
+  def postorder_helper(node, list)
+    if node.nil?
+      return list
+    end
+
+    list << {key: node.key, value: node.value}
+    postorder_helper(node.left, list)
+    postorder_helper(node.right, list)
+    
+  end
+  
+  # Time Complexity: O(n)
+  # Space Complexity: 0(n)
   def postorder
-    raise NotImplementedError
+    return postorder_helper(@root, [])
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  #--------------------------------------------------------------------------#
+  def height_helper(node)
+    if node.nil?
+      return 0
+    end
+    left_length = height_helper(node.left)
+    right_length = height_helper(node.right)
+
+    if left_length > right_length
+      longest_length = left_length
+    else
+      longest_length = right_length
+    end
+    longest_length += 1 # Add one for the current node
+    return longest_length
+
+  end
+  
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def height
-    raise NotImplementedError
+    return height_helper(@root)
   end
 
+  #--------------------------------------------------------------------------#
+  #--------------------------------------------------------------------------#
+
   # Optional Method
   # Time Complexity: 
   # Space Complexity: