From 9edc7aa01df2f652a170435870747a0896b0d83e Mon Sep 17 00:00:00 2001
From: charon2121 <66763177+charon2121@users.noreply.github.com>
Date: Wed, 19 May 2021 08:28:50 +0800
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更新 145.二叉树的后序遍历 python3版本
更新 94.二叉树的中序遍历 python3版本
---
 problems/二叉树的迭代遍历.md | 62 ++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/problems/二叉树的迭代遍历.md b/problems/二叉树的迭代遍历.md
index 2647616b..be2456de 100644
--- a/problems/二叉树的迭代遍历.md
+++ b/problems/二叉树的迭代遍历.md
@@ -160,6 +160,68 @@ Java：
 
 
 Python：
+```python3
+# 前序遍历-迭代-LC144_二叉树的前序遍历
+class Solution:
+    def preorderTraversal(self, root: TreeNode) -> List[int]:
+        # 根结点为空则返回空列表
+        if not root:
+            return []
+        stack = [root]
+        result = []
+        while stack:
+            node = stack.pop()
+            # 中结点先处理
+            result.append(node.val)
+            # 右孩子先入栈
+            if node.right:
+                stack.append(node.right)
+            # 左孩子后入栈
+            if node.left:
+                stack.append(node.left)
+        return result
+        
+# 中序遍历-迭代-LC94_二叉树的中序遍历
+class Solution:
+    def inorderTraversal(self, root: TreeNode) -> List[int]:
+        if not root:
+            return []
+        stack = []  # 不能提前将root结点加入stack中
+        result = []
+        cur = root
+        while cur or stack:
+            # 先迭代访问最底层的左子树结点
+            if cur:     
+                stack.append(cur)
+                cur = cur.left		
+            # 到达最左结点后处理栈顶结点    
+            else:		
+                cur = stack.pop()
+                result.append(cur.val)
+                # 取栈顶元素右结点
+                cur = cur.right	
+        return result
+        
+# 后序遍历-迭代-LC145_二叉树的后序遍历
+class Solution:
+    def postorderTraversal(self, root: TreeNode) -> List[int]:
+        if not root:
+            return []
+        stack = [root]
+        result = []
+        while stack:
+            node = stack.pop()
+            # 中结点先处理
+            result.append(node.val)
+            # 左孩子先入栈
+            if node.left:
+                stack.append(node.left)
+            # 右孩子后入栈
+            if node.right:
+                stack.append(node.right)
+        # 将最终的数组翻转
+        return result[::-1]
+```
 
 
 Go：