# Longest Increasing

### Problem Statement

Given an unsorted array of integers, find the length of longest increasing
subsequence.

For example,

Given [10, 9, 2, 5, 3, 7, 101, 18],

The longest increasing subsequence is [2, 3, 7, 101], therefore the length
is 4. Note that there may be more than one LIS combination, it is only
necessary for you to return the length.

Your algorithm should run in $$O(n^2)$$ complexity.

Could you improve it to $$O(n \log n)$$ time complexity?

#### Credits:

Special thanks to @pbrother for
adding this problem and creating all test cases.

## 题解1 - 双重 for 循环

### 源码分析

1. 初始化数组，初始值为1
2. 根据状态转移方程递推求得lis[i]
3. 遍历lis 数组求得最大值