From 9a1a7ef04780063398576266ee677f1ab86d0068 Mon Sep 17 00:00:00 2001
From: luocaodan <luocaodan@buaa.edu.cn>
Date: Wed, 8 Aug 2018 22:56:45 +0800
Subject: [PATCH] =?UTF-8?q?Update=20=E5=89=91=E6=8C=87=20offer=20=E9=A2=98?=
 =?UTF-8?q?=E8=A7=A3.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 notes/剑指 offer 题解.md | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/notes/剑指 offer 题解.md b/notes/剑指 offer 题解.md
index 47d5d94e..5d9adbea 100644
--- a/notes/剑指 offer 题解.md	
+++ b/notes/剑指 offer 题解.md	
@@ -1298,6 +1298,7 @@ private boolean isSubtreeWithRoot(TreeNode root1, TreeNode root2)
 
 ## 解题思路
 
+### 递归
 ```java
 public void Mirror(TreeNode root)
 {
@@ -1316,6 +1317,28 @@ private void swap(TreeNode root)
 }
 ```
 
+### 迭代
+```java
+public void Mirror(TreeNode root) {
+    if (root == null)
+        return;
+    Stack<TreeNode> stack = new Stack<>();
+    stack.push(root);
+    while (!stack.isEmpty()) {
+        TreeNode p = stack.pop();
+        if (p.left == null && p.right == null)
+            continue;
+        TreeNode left = p.left;
+        p.left = p.right;
+        p.right = left;
+        if (p.left != null)
+            stack.push(p.left);
+        if (p.right != null)
+            stack.push(p.right);
+    }
+}
+```
+
 # 28 对称的二叉树
 
 [NowCder](https://www.nowcoder.com/practice/ff05d44dfdb04e1d83bdbdab320efbcb?tpId=13&tqId=11211&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking)