Andrea Garcia C17

binary_search_trees/array_to_bst.py

@@ -10,4 +10,11 @@ def arr_to_bst(arr):
         Balanced Binary Search Tree using the elements in the array.
         Return the root of the Binary Search Tree.
     """
-    pass
+    while arr: 
+        medi = (len(arr)) // 2
+        root = TreeNode(arr[medi])
+        root.left = arr_to_bst(arr[:medi])
+        root.right = arr_to_bst(arr[medi+1:])   
+        return root
+    else: 
+        return None

tests/test_array_to_bst.py

@@ -10,7 +10,7 @@ def test_will_return_balanced_bst_for_odd_lengthed_list():
     answer = arr_to_bst(arr)
 
     # Assert
-    assert answer.val is 25 and is_bst(answer) and is_balanced_tree(answer)
+    assert answer.val is 25 and is_bst(answer) and is_balanced_tree(answer) and inorder(answer) == arr
 
 def test_will_return_balanced_bst_for_even_lengthed_list():
     # Arrange
@@ -20,7 +20,7 @@ def test_will_return_balanced_bst_for_even_lengthed_list():
     answer = arr_to_bst(arr)
 
     # Assert
-    assert is_bst(answer) and is_balanced_tree(answer)
+    assert is_bst(answer) and is_balanced_tree(answer) and inorder(answer) == arr
 
 def test_will_return_balanced_bst_for_long_list():
     # Arrange
@@ -34,7 +34,7 @@ def test_will_return_balanced_bst_for_long_list():
     answer = arr_to_bst(arr)
 
     # Assert
-    assert is_bst(answer) and is_balanced_tree(answer)
+    assert is_bst(answer) and is_balanced_tree(answer) and inorder(answer) == arr
 
 def test_will_return_none_for_empty_list():
     # Arrange
@@ -93,3 +93,17 @@ def is_balanced_tree(root):
     right_check = is_balanced_tree(root.right)
 
     return left_check and right_check
+
+def inorder_helper(node, values):
+    if not node:
+        return values
+
+    inorder_helper(node.left, values)
+    values.append(node.val)
+    inorder_helper(node.right, values)
+
+    return values
+
+def inorder(node):
+    values = []
+    return inorder_helper(node, values)