diff --git a/README.md b/README.md
index c6860816..da94f661 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@
 * [程序员算法面试中，必须掌握的数组理论知识](https://mp.weixin.qq.com/s/X7R55wSENyY62le0Fiawsg)
 * [这五道数组相关的面试题，你一定要会！](https://mp.weixin.qq.com/s/vdKHt2vFSZEouZASjdWieg)
 * [关于哈希表，你该了解这些！](https://mp.weixin.qq.com/s/g8N6WmoQmsCUw3_BaWxHZA)
-* [精选哈希表相关的面试题](https://mp.weixin.qq.com/s/nxuWv5cUhCPSbAdIHtWgSg)
+* [这六道哈希表相关的面试题，你一定要会！](https://mp.weixin.qq.com/s/nxuWv5cUhCPSbAdIHtWgSg)
 * 精选链表相关的面试题
 * 精选字符串相关的面试题
 * 精选栈与队列相关的面试题
@@ -21,11 +21,62 @@
 
 （持续更新中....）
 
+# LeetCode 刷题攻略： 
+
+刷题顺序：建议先从同一类型里题目开始刷起，同一类型里再从简单到中等到困难刷起，题型顺序建议：**数组-> 链表-> 哈希表->字符串->栈与队列->树**。 
+
+这里我总结了各个类型的经典题目，**初学者可以按照如下顺序来刷题**，算法老手可以按照这个list查缺补漏！
+
+* 数组经典题目
+    * [0035.搜索插入位置](https://github.com/youngyangyang04/leetcode/blob/master/problems/0035.搜索插入位置.md)
+    * [0027.移除元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0027.移除元素.md)
+    * [0026.删除排序数组中的重复项](https://github.com/youngyangyang04/leetcode/blob/master/problems/0026.删除排序数组中的重复项.md)
+    * [0209.长度最小的子数组](https://github.com/youngyangyang04/leetcode/blob/master/problems/0209.长度最小的子数组.md)
+    * [0059.螺旋矩阵II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0059.螺旋矩阵II.md)
+
+* 链表经典题目 
+    * [0203.移除链表元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0203.移除链表元素.md)
+    * [0707.设计链表](https://github.com/youngyangyang04/leetcode/blob/master/problems/0707.设计链表.md)
+    * [0206.翻转链表](https://github.com/youngyangyang04/leetcode/blob/master/problems/0206.翻转链表.md)
+    * [0142.环形链表II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0142.环形链表II.md)
+
+* 哈希表经典题目
+    * [0242.有效的字母异位词](https://github.com/youngyangyang04/leetcode/blob/master/problems/0242.有效的字母异位词.md)
+    * [0383.赎金信](https://github.com/youngyangyang04/leetcode/blob/master/problems/0383.赎金信.md)
+    * [0575.分糖果](https://github.com/youngyangyang04/leetcode/blob/master/problems/0575.分糖果.md)
+    * [0349.两个数组的交集](https://github.com/youngyangyang04/leetcode/blob/master/problems/0349.两个数组的交集.md)
+    * [0202.快乐数](https://github.com/youngyangyang04/leetcode/blob/master/problems/0202.快乐数.md)
+    * [0001.两数之和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0001.两数之和.md)
+    * [0454.四数相加II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0454.四数相加II.md)
+    * [0015.三数之和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0015.三数之和.md)
+    * [0018.四数之和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0018.四数之和.md)
+    * [0219.存在重复元素II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0219.存在重复元素II.md)
+    * 0220.存在重复元素III 
+
+* 字符串经典题目
+    * [0344.反转字符串](https://github.com/youngyangyang04/leetcode/blob/master/problems/0344.反转字符串.md)
+    * [0541.反转字符串II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0541.反转字符串II.md)
+    * [剑指Offer05.替换空格](https://github.com/youngyangyang04/leetcode/blob/master/problems/剑指Offer05.替换空格.md)
+    * [0151.翻转字符串里的单词](https://github.com/youngyangyang04/leetcode/blob/master/problems/0151.翻转字符串里的单词.md)
+    * 延伸左旋转字符串（剑指offer上的题目）
+    * [0028.实现strStr()](https://github.com/youngyangyang04/leetcode/blob/master/problems/0028.实现strStr().md)
+    * [0459.重复的子字符串](https://github.com/youngyangyang04/leetcode/blob/master/problems/0459.重复的子字符串.md)
+
+* 栈与队列经典题目
+    * [0232.用栈实现队列](https://github.com/youngyangyang04/leetcode/blob/master/problems/0232.用栈实现队列.md)
+    * [0225.用队列实现栈](https://github.com/youngyangyang04/leetcode/blob/master/problems/0225.用队列实现栈.md)
+    * [0020.有效的括号](https://github.com/youngyangyang04/leetcode/blob/master/problems/0020.有效的括号.md)
+    * [1047.删除字符串中的所有相邻重复项](https://github.com/youngyangyang04/leetcode/blob/master/problems/1047.删除字符串中的所有相邻重复项.md)
+    * [0239.滑动窗口最大值](https://github.com/youngyangyang04/leetcode/blob/master/problems/0239.滑动窗口最大值.md)
+    * [0347.前K个高频元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0347.前K个高频元素.md)
+
+* 二叉树经典题目 
+
+
+（待补充.....）
 
 # LeetCode 最强题解:
 
-刷题顺序：建议先从同一类型里题目开始刷起，同一类型里再从简单到中等到困难刷起，题型顺序建议：数组-> 链表-> 哈希表->字符串->栈与队列->树
-
 |题目 | 类型 | 难度 | 解题方法 |
 |---|---| ---| --- |
 |[0001.两数之和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0001.两数之和.md) | 数组|简单|**暴力** **哈希**| 
@@ -71,6 +122,8 @@
 |[0450.删除二叉搜索树中的节点](https://github.com/youngyangyang04/leetcode/blob/master/problems/0450.删除二叉搜索树中的节点.md) |树 |中等|**递归**|
 |[0434.字符串中的单词数](https://github.com/youngyangyang04/leetcode/blob/master/problems/0434.字符串中的单词数.md) |字符串 |简单|**模拟**|
 |[0454.四数相加II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0454.四数相加II.md) |哈希表 |中等| **哈希**|
+|[0459.重复的子字符串](https://github.com/youngyangyang04/leetcode/blob/master/problems/0459.重复的子字符串.md) |字符创 |简单| **KMP**|
+|[0541.反转字符串II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0541.反转字符串II.md) |字符串 |简单| **模拟**|
 |[0575.分糖果](https://github.com/youngyangyang04/leetcode/blob/master/problems/0575.分糖果.md) |哈希表 |简单|**哈希**|
 |[0617.合并二叉树](https://github.com/youngyangyang04/leetcode/blob/master/problems/0617.合并二叉树.md) |树 |简单|**递归** **迭代**|
 |[0654.最大二叉树](https://github.com/youngyangyang04/leetcode/blob/master/problems/0654.最大二叉树.md) |树 |中等|**递归**|
diff --git a/problems/0094.二叉树的中序遍历.md b/problems/0094.二叉树的中序遍历.md
index f0f52d76..8e8890f8 100644
--- a/problems/0094.二叉树的中序遍历.md
+++ b/problems/0094.二叉树的中序遍历.md
@@ -11,11 +11,11 @@ https://leetcode-cn.com/problems/binary-tree-inorder-traversal/
 ```
 class Solution {
 public:
-    void traversal(TreeNode* root, vector<int>& vec) {
-        if (root == NULL) return;
-        traversal(root->left, vec);
-        vec.push_back(root->val);
-        traversal(root->right, vec);
+    void traversal(TreeNode* cur, vector<int>& vec) {
+        if (cur == NULL) return;
+        traversal(cur->left, vec);
+        vec.push_back(cur->val);
+        traversal(cur->right, vec);
     }
     vector<int> inorderTraversal(TreeNode* root) {
         vector<int> result;
diff --git a/problems/0144.二叉树的前序遍历.md b/problems/0144.二叉树的前序遍历.md
index 221f6a41..01acf237 100644
--- a/problems/0144.二叉树的前序遍历.md
+++ b/problems/0144.二叉树的前序遍历.md
@@ -11,11 +11,11 @@ https://leetcode-cn.com/problems/binary-tree-preorder-traversal/
 ```
 class Solution {
 public:
-    void traversal(TreeNode* root, vector<int>& vec) {
-        if (root == NULL) return;
-        vec.push_back(root->val);
-        traversal(root->left, vec);
-        traversal(root->right, vec);
+    void traversal(TreeNode* cur, vector<int>& vec) {
+        if (cur == NULL) return;
+        vec.push_back(cur->val);
+        traversal(cur->left, vec);
+        traversal(cur->right, vec);
     }
     vector<int> preorderTraversal(TreeNode* root) {
         vector<int> result;