# 344. Reverse String

#### Easy

***

Write a function that reverses a string. The input string is given as an array of characters `s`.

You must do this by modifying the input array [in-place](https://en.wikipedia.org/wiki/In-place_algorithm) with `O(1)` extra memory.

 

**Example 1:**

```
Input: s = ["h","e","l","l","o"]
Output: ["o","l","l","e","h"]
```

**Example 2:**

```
Input: s = ["H","a","n","n","a","h"]
Output: ["h","a","n","n","a","H"]
```

 

**Constraints:**

* `1 <= s.length <= 105`
* `s[i]` is a [printable ascii character](https://en.wikipedia.org/wiki/ASCII#Printable_characters).

```python
class Solution:
    def reverseString(self, s: List[str]) -> None:
        left, right = 0, len(s)-1
        while left <= right:
            s[left], s[right] = s[right], s[left]
            left += 1
            right -= 1
```