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# 344. Reverse String

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

Do not allocate extra space for another array, you must do this by **modifying the input array** [**in-place**](https://en.wikipedia.org/wiki/In-place_algorithm) with O(1) extra memory.

You may assume all the characters consist of [printable ascii characters](https://en.wikipedia.org/wiki/ASCII#Printable_characters).

**Example 1:**

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

**Example 2:**

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

```
# @param {Character[]} s
# @return {Void} Do not return anything, modify s in-place instead.
def reverse_string(s)
  s.reverse!
end
```