Spruce - Michelle Morales

binary_search_tree/tree.py

@@ -8,41 +8,137 @@ def __init__(self, key, val = None):
         self.left = None
         self.right = None
 
-
-
 class Tree:
     def __init__(self):
         self.root = None
 
-    # Time Complexity: 
-    # Space Complexity: 
+    # Time Complexity: O(logn)
+    # Space Complexity: O(1)
     def add(self, key, value = None):
-        pass
+        if self.root == None:
+            self.root = TreeNode(key, value)
+            return
+
+        current = self.root
 
-    # Time Complexity: 
-    # Space Complexity: 
+        while current != None:
+            if key < current.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(LogN)
+    # Space Complexity: O(1)
     def find(self, key):
-        pass
+        current = self.root
 
-    # Time Complexity: 
-    # Space Complexity: 
+        while current != None:
+            if current.key == key:
+                return current.value
+            elif key < current.key:
+                current = current.left
+            else:
+                current = current.right
+
+        return None
+
+    # This method returns an array of all the elements in the tree, in order.
+    # Time Complexity: O(N)
+    # Space Complexity: O(N)
     def inorder(self):
-        pass
+        """
+        if this is null
+        return
+        inOrder(left)
+        visit this
+        inOrder(right)
+        """
+        current = self.root
+        result = []
 
-    # Time Complexity: 
-    # Space Complexity:     
+        return self.inorder_helper(current, result)
+
+    def inorder_helper(self, current, result):
+        if current is None:
+            return result
+
+        current.left = self.inorder_helper(current.left, result)
+        result.append({"key": current.key, "value": current.value})
+        current.right = self.inorder_helper(current.right, result)
+        return result
+
+    # This method returns an array of all the elements in a preorder fashion (root, left, right)
+    # Time Complexity: O(N)
+    # Space Complexity:  O(N)     
     def preorder(self):
-        pass
+        current = self.root
+        result = []
+
+        return self.preorder_helper(current, result)
+
+    def preorder_helper(self, current, result):
+        if current is None:
+            return result
+
+        result.append({"key": current.key, "value": current.value})
+        current.left = self.preorder_helper(current.left, result)
+        current.right = self.preorder_helper(current.right, result)
 
-    # Time Complexity: 
-    # Space Complexity:     
+        return result
+
+    # This method returns an array of all the elements in a postorder fashion (left, right , root).
+    # Time Complexity: O(N)
+    # Space Complexity: O(N)   
     def postorder(self):
-        pass
+        current = self.root
+        result = []
+
+        return self.postorder_helper(current, result)
+
+    def postorder_helper(self, current, result):
+        if current is None:
+            return result
 
-    # Time Complexity: 
-    # Space Complexity:     
+        current.left = self.postorder_helper(current.left, result)
+        current.right = self.postorder_helper(current.right, result)
+        result.append({"key": current.key, "value": current.value})
+
+        return result
+
+    # This method returns the height of the binary search tree
+    # Time Complexity: O(N)
+    # Space Complexity: O(N)    
     def height(self):
-        pass
+        height = 0
+        current = self.root
+
+        if current is None:
+            return height
+
+        return self.height_helper(current, height)
+
+    def height_helper(self, current, height):
+        if current is None:
+            return height
+
+        leftAns = self.height_helper(current.left, height)
+        rightAns = self.height_helper(current.right, height)
+
+        return max(leftAns, rightAns) + 1    
+    # # Recursively call height of each node
+    #     leftAns = height(self.root.left)
+    #     rightAns = height(self.root.right)
+
+    # # Return max(leftHeight, rightHeight) at each iteration
+    #     return max(leftAns, rightAns) + 1
 
 
 #   # Optional Method
@@ -51,9 +147,6 @@ def height(self):
     def bfs(self):
         pass
 
-
-
-
 #   # Useful for printing
     def to_s(self):
         return f"{self.inorder()}"

tests/test_binary_search_tree.py

@@ -1,3 +1,4 @@
+from unittest import skip
 import pytest
 from binary_search_tree.tree import Tree
 
@@ -202,11 +203,11 @@ def test_will_report_height_of_unbalanced_tree():
 
     assert unbalanced_tree.height() == 5
 
-
+@pytest.mark.skip
 def test_bfs_with_empty_tree(empty_tree):
     assert empty_tree.bfs() == []
 
-
+@pytest.mark.skip
 def test_bfs_with_tree_with_nodes(tree_with_nodes):
     expected_answer = [
         {