# 34: Longest increasing subsequence

Given an `array`

of `integers`

, find the `length`

of the `longest`

increasing subsequence (LIS)

`Example 1`

```
Input: [3, 2, 9, 4, 10, 11, 7]
Output: 4
```

Explanation:

`[3, 9, 10, 11]`

or`[2, 9, 10, 11]`

`Example 2`

```
Input: [3, 2, 1]
Output: 1
```