From 08278636619344c55515ff712083ca9f4759c5e8 Mon Sep 17 00:00:00 2001
From: Beena P Jha <jhabeena95@gmail.com>
Date: Tue, 29 Oct 2019 21:10:25 +0530
Subject: [PATCH] Create Tree Traversal - Postorder

---
 Tree Traversal - Postorder | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Tree Traversal - Postorder

diff --git a/Tree Traversal - Postorder b/Tree Traversal - Postorder
new file mode 100644
index 0000000..c42a17e
--- /dev/null
+++ b/Tree Traversal - Postorder	
@@ -0,0 +1,31 @@
+
+##Iterative Solution##
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def postorderTraversal(self, root: TreeNode) -> List[int]:
+        #left->right->root
+        stack=[(False,root)]
+        res=[]
+        while stack:
+            flag,val=stack.pop()
+            if val:
+                if not flag:
+                    stack.append((True,val))
+                    stack.append((False,val.right))
+                    stack.append((False,val.left))
+                else:
+                    res.append(val.val)
+        return res
+
+
+##Recursive Solution ##
+      if not root:
+            return []
+        else:
+            return self.postorderTraversal(root.left) + self.postorderTraversal(root.right) + [root.val]