Time: 43 ms (6.95%), Space: 16.6 MB (20.02%) - LeetHub

Author: Deepak5113

0145-binary-tree-postorder-traversal/0145-binary-tree-postorder-traversal.py

@@ -0,0 +1,24 @@
+# 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 postorderTraversal(self, root: Optional[TreeNode]) -> List[int]:
+        if not root:
+            return []
+        
+        stack1, stack2 = [], []
+        stack1.append(root)
+        
+        while stack1:
+            node = stack1.pop()
+            stack2.append(node)
+            
+            if node.left:
+                stack1.append(node.left)
+            if node.right:
+                stack1.append(node.right)
+        
+        return [node.val for node in reversed(stack2)]