From c5b691b91dc85cc16304fb9884d9db4afadb88e0 Mon Sep 17 00:00:00 2001
From: zhicheng lee <904688436@qq.com>
Date: Wed, 8 Dec 2021 16:49:06 +0800
Subject: [PATCH 1/2] =?UTF-8?q?Update=200236.=E4=BA=8C=E5=8F=89=E6=A0=91?=
 =?UTF-8?q?=E7=9A=84=E6=9C=80=E8=BF=91=E5=85=AC=E5=85=B1=E7=A5=96=E5=85=88?=
 =?UTF-8?q?.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

更新 0236题 Java版本代码
---
 .../0236.二叉树的最近公共祖先.md    | 40 +++++++------------
 1 file changed, 14 insertions(+), 26 deletions(-)

diff --git a/problems/0236.二叉树的最近公共祖先.md b/problems/0236.二叉树的最近公共祖先.md
index 4182999f..6d26e376 100644
--- a/problems/0236.二叉树的最近公共祖先.md
+++ b/problems/0236.二叉树的最近公共祖先.md
@@ -221,42 +221,30 @@ public:
 
 
 ## Java 
+
 ```Java
 class Solution {
     public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
-        return lowestCommonAncestor1(root, p, q);
-    }
-    public TreeNode lowestCommonAncestor1(TreeNode root, TreeNode p, TreeNode q) {
-        if (root == null || root == p || root == q) {
+        if (root == null || root == p || root == q) { // 递归结束条件
             return root;
         }
-        TreeNode left = lowestCommonAncestor1(root.left, p, q);
-        TreeNode right = lowestCommonAncestor1(root.right, p, q);
-        if (left != null && right != null) {// 左右子树分别找到了，说明此时的root就是要求的结果
-            return root;
-        }
-        if (left == null) {
+
+        // 后序遍历
+        TreeNode left = lowestCommonAncestor(root.left, p, q);
+        TreeNode right = lowestCommonAncestor(root.right, p, q);
+
+        if(left == null && right == null) { // 若未找到节点 p 或 q
+            return null;
+        }else if(left == null && right != null) { // 若找到一个节点
             return right;
+        }else if(left != null && right == null) { // 若找到一个节点
+            return left;
+        }else { // 若找到两个节点
+            return root;
         }
-        return left;
     }
 }
-```
 
-
-```java
-// 代码精简版
-class Solution {
-    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
-        if (root == null || root.val == p.val ||root.val == q.val) return root;
-        TreeNode left = lowestCommonAncestor(root.left,p,q);
-        TreeNode right = lowestCommonAncestor(root.right,p,q);
-        if (left != null && right != null) return root;
-        else if (left == null && right != null) return right;
-        else if (left != null && right == null) return left;
-        else return null;
-    }
-}
 ```
 
 ## Python 

From 38b8b343c931019e76d7692b99ee7d397538494c Mon Sep 17 00:00:00 2001
From: zhicheng lee <904688436@qq.com>
Date: Thu, 9 Dec 2021 11:16:22 +0800
Subject: [PATCH 2/2] =?UTF-8?q?=E6=9B=B4=E6=96=B0=20=E9=A2=98=E7=9B=AE0701?=
 =?UTF-8?q?=20Java=E7=89=88=E6=9C=AC=E4=BB=A3=E7=A0=81?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0701.二叉搜索树中的插入操作.md | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/problems/0701.二叉搜索树中的插入操作.md b/problems/0701.二叉搜索树中的插入操作.md
index 5d63ce58..1e6ab47e 100644
--- a/problems/0701.二叉搜索树中的插入操作.md
+++ b/problems/0701.二叉搜索树中的插入操作.md
@@ -236,16 +236,13 @@ class Solution {
 ```java
 class Solution {
     public TreeNode insertIntoBST(TreeNode root, int val) {
-        return buildTree(root, val);
-    }
-
-    public TreeNode buildTree(TreeNode root, int val){
         if (root == null) // 如果当前节点为空，也就意味着val找到了合适的位置，此时创建节点直接返回。
             return new TreeNode(val);
+            
         if (root.val < val){
-            root.right = buildTree(root.right, val); // 递归创建右子树
+            root.right = insertIntoBST(root.right, val); // 递归创建右子树
         }else if (root.val > val){
-            root.left = buildTree(root.left, val); // 递归创建左子树
+            root.left = insertIntoBST(root.left, val); // 递归创建左子树
         }
         return root;
     }