Create binary tree inorder traversal.py

binary tree inorder traversal

@@ -0,0 +1,21 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:        
+    def inorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
+        inorder = []
+        stack = [root]
+        while stack:
+            root = stack[-1]
+            if root:
+                stack.append(root.left)
+            else:
+                stack.pop()
+                if stack:
+                    root = stack.pop()
+                    inorder.append(root.val)
+                    stack.append(root.right)
+        return inorder