not a stack oops

Author: stevestar888

Diff for: 226-invert_binary_tree.py

@@ -30,6 +30,7 @@ def invertTree(self, root):
 
         return root
 
+    
     """
     Iterative
     
@@ -45,18 +46,18 @@ def invertTree(self, root):
         if not root:
             return None
 
-        stack = deque()
-        stack.append(root)
+        queue = deque()
+        queue.append(root)
 
-        while stack:
-            node = stack.popleft()
+        while queue:
+            node = queue.popleft()
 
             #swap the left & right children with each other
             node.left, node.right = node.right, node.left
 
             if node.left:
-                stack.append(node.left)
+                queue.append(node.left)
             if node.right:
-                stack.append(node.right)
+                queue.append(node.right)
 
         return root