From aedda8732e662a76a4d4e6916da0f31230487889 Mon Sep 17 00:00:00 2001
From: hailincai <hailin.cai.neulion@gmail.com>
Date: Thu, 14 Oct 2021 07:16:33 -0400
Subject: [PATCH 1/2] =?UTF-8?q?Update=200707.=E8=AE=BE=E8=AE=A1=E9=93=BE?=
 =?UTF-8?q?=E8=A1=A8.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Format the ListNode definition for java code
---
 problems/0707.设计链表.md | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/problems/0707.设计链表.md b/problems/0707.设计链表.md
index 64472506..ba0e7e3b 100644
--- a/problems/0707.设计链表.md
+++ b/problems/0707.设计链表.md
@@ -282,12 +282,12 @@ Java：
 ```Java
 //单链表
 class ListNode {
-int val;
-ListNode next;
-ListNode(){}
-ListNode(int val) {
-this.val=val;
-}
+    int val;
+    ListNode next;
+    ListNode(){}
+    ListNode(int val) {
+        this.val=val;
+    }
 }
 class MyLinkedList {
     //size存储链表元素的个数

From e037b8755822d926de2b44eff180824f2baa4b7c Mon Sep 17 00:00:00 2001
From: hailincai <hailin.cai.neulion@gmail.com>
Date: Thu, 14 Oct 2021 07:58:33 -0400
Subject: [PATCH 2/2] =?UTF-8?q?Update=200206.=E7=BF=BB=E8=BD=AC=E9=93=BE?=
 =?UTF-8?q?=E8=A1=A8.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

增加Java从后向前递归的代码
---
 problems/0206.翻转链表.md | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/problems/0206.翻转链表.md b/problems/0206.翻转链表.md
index ec6f3dca..3e2a22be 100644
--- a/problems/0206.翻转链表.md
+++ b/problems/0206.翻转链表.md
@@ -164,6 +164,25 @@ class Solution {
 }
 ```
 
+```java
+// 从后向前递归
+class Solution {
+    ListNode reverseList(ListNode head) {
+        // 边缘条件判断
+        if(head == null) return null;
+        if (head.next == null) return head;
+        
+        // 递归调用，翻转第二个节点开始往后的链表
+        ListNode last = reverseList(head.next);
+        // 翻转头节点与第二个节点的指向
+        head.next.next = head;
+        // 此时的 head 节点为尾节点，next 需要指向 NULL
+        head.next = null;
+        return last;
+    } 
+}
+```
+
 Python迭代法：
 ```python
 #双指针