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# 0301. Remove Invalid Parentheses

<https://leetcode.com/problems/remove-invalid-parentheses>

## Description

Given a string `s` that contains parentheses and letters, remove the minimum number of invalid parentheses to make the input string valid.

Return *all the possible results*. You may return the answer in **any order**.

**Example 1:**

```
**Input:** s = "()())()"
**Output:** ["(())()","()()()"]
```

**Example 2:**

```
**Input:** s = "(a)())()"
**Output:** ["(a())()","(a)()()"]
```

**Example 3:**

```
**Input:** s = ")("
**Output:** [""]
```

**Constraints:**

* `1 <= s.length <= 25`
* `s` consists of lowercase English letters and parentheses `'('` and `')'`.
* There will be at most `20` parentheses in `s`.