Fire - Alice D

.rakeTasks

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Settings><!--This file was automatically generated by Ruby plugin.
+You are allowed to: 
+1. Remove rake task
+2. Add existing rake tasks
+To add existing rake tasks automatically delete this file and reload the project.
+--><RakeGroup description="" fullCmd="" taksId="rake"><RakeTask description="Run tests" fullCmd="test" taksId="test" /><RakeTask description="" fullCmd="default" taksId="default" /></RakeGroup></Settings>

lib/tree.rb

@@ -16,49 +16,133 @@ def initialize
     @root = nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
-  def add(key, value)
-    raise NotImplementedError
+  # Time Complexity: O(log n); although if the tree is not balanced, this could be O(n)
+  # Space Complexity: O(1)
+  def add(key, value = nil)
+    if @root.nil?
+      @root = TreeNode.new(key, value)
+      return @root.value
+    end
+
+    current = @root
+
+    while key <= current.key || key > current.key
+      if key == current.key
+        "This key is already taken."
+      elsif key < current.key
+        if current.left.nil?
+          current.left = TreeNode.new(key,value)
+          return value
+        else
+          current = current.left
+        end
+      else
+        if current.right.nil?
+          current.right = TreeNode.new(key,value)
+          return value
+        else
+          current = current.right
+        end
+      end
+    end
+
   end
 
-  # Time Complexity: 
+
+  # Time Complexity: O(log n); although if the tree is not balanced, this could be O(n)
   # Space Complexity: 
   def find(key)
-    raise NotImplementedError
+    current = @root
+    while current != nil
+      if current.key == key
+        return current.value
+      elsif current.key > key
+        current = current.left
+      elsif current.key < key
+        current = current.right
+      end
+    end
+    return nil
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def inorder
-    raise NotImplementedError
+    array = []
+    current = @root
+    inorder_helper(array, current)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  def inorder_helper(array, current)
+    return array if current.nil?
+
+    #left
+    inorder_helper(array, current.left)
+    #middle
+    array << {:key => current.key, :value => current.value}
+    #right
+    inorder_helper(array, current.right)
+
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def preorder
-    raise NotImplementedError
+    array = []
+    current = @root
+    preorder_helper(array, current)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  def preorder_helper(array, current)
+    return array if current.nil?
+    #middle
+    array << {:key => current.key, :value => current.value}
+    #left
+    preorder_helper(array, current.left)
+    #right
+    preorder_helper(array, current.right)
+
+  end
+
+  # Time Complexity: O(n)
+  # Space Complexity: O(n)
   def postorder
-    raise NotImplementedError
+    array = []
+    current = @root
+    postorder_helper(array, current)
   end
 
-  # Time Complexity: 
-  # Space Complexity: 
+  def postorder_helper(array, current)
+    return array if current.nil?
+
+    #left
+    postorder_helper(array, current.left)
+    #right
+    postorder_helper(array, current.right)
+    #middle
+    array << {:key => current.key, :value => current.value}
+
+  end
+
+  # Time Complexity: O(log n); although if the tree is not balanced, this could be O(n)
+  # Space Complexity: O(1)
   def height
-    raise NotImplementedError
+    height_helper(@root)
+  end
+
+  def height_helper(root)
+    return 0 if root.nil?
+    [1 + height_helper(root.left), 1 + height_helper(root.right)].max
   end
 
   # Optional Method
   # Time Complexity: 
   # Space Complexity: 
   def bfs
-    raise NotImplementedError
+    # optional
   end
 
+
   # Useful for printing
   def to_s
     return "#{self.inorder}"