# leetcode

**Repository Path**: litarussell/leetcode

## Basic Information

- **Project Name**: leetcode
- **Description**: leetcode算法练习
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-11-02
- **Last Updated**: 2021-05-26

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# leetcode
leetcode算法练习

# 动态规划 回文串 需要注意dp的计算顺序, 被依赖的dp状态需要先通过已知的状态计算出来
* [5. 最长回文子串](https://leetcode-cn.com/problems/longest-palindromic-substring/)
* [516. 最长回文子序列](https://leetcode-cn.com/problems/longest-palindromic-subsequence/)
* [647. 回文子串](https://leetcode-cn.com/problems/palindromic-substrings/)
* [300. 最长上升子序列](https://leetcode-cn.com/problems/longest-increasing-subsequence/) 贪心算法比较巧妙, 贪心策略是最长上升序列最后加上的数要尽可能的小

* [53. 最大子序和](https://leetcode-cn.com/problems/maximum-subarray/) dp优化的思路都是看转移方程所依赖的状态, 该题只依赖于上一个最大子序和, 只需要一个变量来记录上一个状态
* [152. 乘积最大子数组](https://leetcode-cn.com/problems/maximum-product-subarray/) 需要考虑负数 dp会有两个状态转移方程 可优化为两个变量 因为下一个状态只和前面的最大乘积 最小乘积有关

# 贪心算法 主要是贪心策略 
* [621. 任务调度器](https://leetcode-cn.com/problems/task-scheduler/): 贪心算法、队列
* [406. 根据身高重建队列](https://leetcode-cn.com/problems/queue-reconstruction-by-height/)
* [300. 最长上升子序列](https://leetcode-cn.com/problems/longest-increasing-subsequence/)
* [452. 用最少数量的箭引爆气球](https://leetcode-cn.com/problems/minimum-number-of-arrows-to-burst-balloons/)
* [435. 无重叠区间](https://leetcode-cn.com/problems/non-overlapping-intervals/)
* [402. 移掉k位数字](https://leetcode-cn.com/problems/remove-k-digits/)
* [738. 单调递增的数字](https://leetcode-cn.com/problems/monotone-increasing-digits/): 贪心策略->为了保证数字从高位开始要尽可能不变, 

* [x] [767. 重构字符串](https://leetcode-cn.com/problems/reorganize-string/)

## 回溯算法:
* [46. 全排列](https://leetcode-cn.com/problems/permutations/)
* [47. 全排列 II](https://leetcode-cn.com/problems/permutations-ii/) 剪枝排除重复项
* [39. 组合总和](https://leetcode-cn.com/problems/combination-sum/) 考虑剪枝
* [17. 电话号码的字母组合](https://leetcode-cn.com/problems/letter-combinations-of-a-phone-number/) 隐式回溯
* [22. 括号生成](https://leetcode-cn.com/problems/generate-parentheses/)
* [39. 组合总和](https://leetcode-cn.com/problems/combination-sum/)
* [40. 组合总和 II](https://leetcode-cn.com/problems/combination-sum-ii/) 
  > 组合总和两题的不同在于每个元素能否重复使用
* [77. 组合](https://leetcode-cn.com/problems/combinations/)
* [78. 子集](https://leetcode-cn.com/problems/subsets/)
* [90. 子集 II](https://leetcode-cn.com/problems/subsets-ii/)
* [93. 复原IP地址](https://leetcode-cn.com/problems/restore-ip-addresses/)
* [784. 字母大小写全排列](https://leetcode-cn.com/problems/letter-case-permutation/)

- [x] [51. N 皇后](https://leetcode-cn.com/problems/n-queens/)
* [60. 第k个排列](https://leetcode-cn.com/problems/permutation-sequence/)

# 二叉树
* [222. 完全二叉树的节点个数](https://leetcode-cn.com/problems/count-complete-tree-nodes/) 完全二叉树 二分 逐个确认满二叉树的子树

# 前缀和: 前缀和之间的差
* [560. 和为k的子数组](https://leetcode-cn.com/problems/subarray-sum-equals-k/submissions/)
* [437. 路径总和 III](https://leetcode-cn.com/problems/path-sum-iii/)
* [454. 四数相加 II](https://leetcode-cn.com/problems/4sum-ii/)

## 路径和
* [112. 路径总和](https://leetcode-cn.com/problems/path-sum/)
* [113. 路径总和 II](https://leetcode-cn.com/problems/path-sum-ii/)
* [437. 路径总和 III](https://leetcode-cn.com/problems/path-sum-iii/)
* [687. 最长同值路径](https://leetcode-cn.com/problems/longest-univalue-path/)

# 最长上升子序列 重叠 不重叠 dp 贪心
* [300. 最长上升子序列](https://leetcode-cn.com/problems/longest-increasing-subsequence/)
* [435. 无重叠区间](https://leetcode-cn.com/problems/non-overlapping-intervals/)
* [452. 用最少数量的箭引爆气球](https://leetcode-cn.com/problems/minimum-number-of-arrows-to-burst-balloons/)

# 单调栈
* [739. 每日温度](https://leetcode-cn.com/problems/daily-temperatures/)

- [x] [42. 接雨水](https://leetcode-cn.com/problems/trapping-rain-water/)
- [x] [84. 柱状图中最大的矩形](https://leetcode-cn.com/problems/largest-rectangle-in-histogram/)

# 拓扑排序
* [207. 课程表](https://leetcode-cn.com/problems/course-schedule)
* [210. 课程表 II](https://leetcode-cn.com/problems/course-schedule-ii/)