|[0027.移除元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0027.移除元素.md)|数组|简单|**暴力****双指针/快慢指针/双指针**|

|[0028.实现strStr()](https://github.com/youngyangyang04/leetcode/blob/master/problems/0028.实现strStr().md)|字符串|简单|**KMP**|

|[0031.下一个排列](https://github.com/youngyangyang04/leetcode/blob/master/problems/0031.下一个排列.md)|数组|中等|**模拟** 这道题目还是有难度的|

|[0034.在排序数组中查找元素的第一个和最后一个位置](https://github.com/youngyangyang04/leetcode/blob/master/problems/0031.下一个排列.md)|数组|中等|**二分查找**比35.搜索插入位置难一些|

|[0034.在排序数组中查找元素的第一个和最后一个位置](https://github.com/youngyangyang04/leetcode/blob/master/problems/0034.在排序数组中查找元素的第一个和最后一个位置.md)|数组|中等|**二分查找**比35.搜索插入位置难一些|

|[0035.搜索插入位置](https://github.com/youngyangyang04/leetcode/blob/master/problems/0035.搜索插入位置.md)|数组|简单|**暴力****二分**|

|[0037.解数独](https://github.com/youngyangyang04/leetcode/blob/master/problems/0037.解数独.md)|回溯|困难|**回溯**|

|[0039.组合总和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0039.组合总和.md)|数组/回溯|中等|**回溯**|

|[0113.路径总和II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0113.路径总和II.md)|二叉树树|简单|**深度优先搜索/递归****回溯****栈**|

|[0116.填充每个节点的下一个右侧节点指针](https://github.com/youngyangyang04/leetcode/blob/master/problems/0116.填充每个节点的下一个右侧节点指针.md)|二叉树|中等|**递归****迭代/广度优先搜索**|

|[0117.填充每个节点的下一个右侧节点指针II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0117.填充每个节点的下一个右侧节点指针II.md)|二叉树|中等|**递归****迭代/广度优先搜索**|

|[0122.买卖股票的最佳时机II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0122.买卖股票的最佳时机II.md)|贪心|简单|**贪心**|

|[0121.买卖股票的最佳时机](https://github.com/youngyangyang04/leetcode/blob/master/problems/0121.买卖股票的最佳时机.md)|动态规划|简单|**贪心****动态规划**|

|[0122.买卖股票的最佳时机II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0122.买卖股票的最佳时机II.md)|动态规划|简单|**贪心****动态规划**|

|[0123.买卖股票的最佳时机III](https://github.com/youngyangyang04/leetcode/blob/master/problems/0122.买卖股票的最佳时机II.md)|动态规划|中等|**贪心****动态规划**|

|[0127.单词接龙](https://github.com/youngyangyang04/leetcode/blob/master/problems/0127.单词接龙.md)|广度优先搜索|中等|**广度优先搜索**|

|[0129.求根到叶子节点数字之和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0129.求根到叶子节点数字之和.md)|二叉树|中等|**递归/回溯** 递归里隐藏着回溯，和113.路径总和II类似|

|[0131.分割回文串](https://github.com/youngyangyang04/leetcode/blob/master/problems/0131.分割回文串.md)|回溯|中等|**回溯**|

|[0150.逆波兰表达式求值](https://github.com/youngyangyang04/leetcode/blob/master/problems/0150.逆波兰表达式求值.md)|栈|中等|**栈**|

|[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)|字符串|中等|**模拟/双指针**|

|[0155.最小栈](https://github.com/youngyangyang04/leetcode/blob/master/problems/0155.最小栈.md)|栈|简单|**栈**|

|[0188.买卖股票的最佳时机IV](https://github.com/youngyangyang04/leetcode/blob/master/problems/0188.买卖股票的最佳时机IV.md)|动态规划|困难|**动态规划**|

|[0199.二叉树的右视图](https://github.com/youngyangyang04/leetcode/blob/master/problems/0199.二叉树的右视图.md)|二叉树|中等|**广度优先遍历/队列**|

|[0202.快乐数](https://github.com/youngyangyang04/leetcode/blob/master/problems/0202.快乐数.md)|哈希表|简单|**哈希**|

|[0203.移除链表元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0203.移除链表元素.md)|链表|简单|**模拟****虚拟头结点**|