Lilly C16

binary_search_tree/tree.py

@@ -14,35 +14,122 @@ class Tree:
     def __init__(self):
         self.root = None
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # Time Complexity: O(log(n))
+    # Space Complexity: O(n)
     def add(self, key, value = None):
-        pass
-
-    # Time Complexity: 
-    # Space Complexity: 
+        if self.root == None:
+            self.root = TreeNode(key, value)
+            return
+
+        current = self.root
+        while current != None:
+            if current.key > key:
+                if current.left == None:
+                    current.left = TreeNode(key, value)
+                    return
+                else:
+                    current = current.left
+            else:
+                if current.right == None:
+                    current.right = TreeNode(key, value)
+                    return
+                else:
+                    current = current.right
+
+    # Time Complexity: o(1)
+    # Space Complexity: O(n)
+    # search for a node in the tree
     def find(self, key):
-        pass
+        current = self.root
+        while current != None:
+            if current.key == key:
+                return current.value
+            elif current.key > key:
+                current = current.left
+            else:
+                current = current.right
+        return None
+
+
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # Time Complexity: O(n)
+    # Space Complexity: O(n) 
+    def inorder_helper(self, current, result):
+        if current == None:
+            return result
+        else:
+            result = self.inorder_helper(current.left, result)
+            result.append({"key":current.key, "value":current.value})
+            result = self.inorder_helper(current.right, result)
+            return result
+
     def inorder(self):
-        pass
+        result = []
+        current = self.root
+        if current == None:
+            return result
+        else:
+            result = self.inorder_helper(current, result)
+            return result
 
-    # Time Complexity: 
-    # Space Complexity:     
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)  
+    def preorder_helper(self, current, result):
+        if current == None:
+            return result
+        else:
+            result.append({"key":current.key, "value":current.value})
+            result = self.preorder_helper(current.left, result)
+            result = self.preorder_helper(current.right, result)
+            return result
     def preorder(self):
-        pass
+        result = []
+        current = self.root
+        if current == None:
+            return result
+        else:
+            result = self.preorder_helper(current, result)
+            return result
+
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
+    def postorder_helper(self, current, result):
+        if current == None:
+            return result
+        else:
+            result = self.postorder_helper(current.left, result)
+            result = self.postorder_helper(current.right, result)
+            result.append({"key":current.key, "value":current.value})
+            return result   
 
-    # Time Complexity: 
-    # Space Complexity:     
     def postorder(self):
-        pass
+        result = []
+        current = self.root
+        if current == None:
+            return result
+        else:
+            result = self.postorder_helper(current, result)
+            return result
+
+    # Time Complexity: O(n)
+    # Space Complexity: O(n)
+    def height_helper(self, current):
+        if current == None:
+            return 0
+        else:
+            left_height = self.height_helper(current.left)
+            right_height = self.height_helper(current.right)
+            if left_height > right_height:
+                return left_height + 1
+            else:
+                return right_height + 1
 
-    # Time Complexity: 
-    # Space Complexity:     
     def height(self):
-        pass
+        current = self.root
+        if current == None:
+            return 0
+        else:
+            return self.height_helper(current)
 
 
 #   # Optional Method