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# 1980. Find Unique Binary String

<https://leetcode.com/problems/find-unique-binary-string>

## Description

Given an array of strings `nums` containing `n` **unique** binary strings each of length `n`, return *a binary string of length* `n` *that **does not appear** in* `nums`*. If there are multiple answers, you may return **any** of them*.

**Example 1:**

```
**Input:** nums = ["01","10"]
**Output:** "11"
**Explanation:** "11" does not appear in nums. "00" would also be correct.
```

**Example 2:**

```
**Input:** nums = ["00","01"]
**Output:** "11"
**Explanation:** "11" does not appear in nums. "10" would also be correct.
```

**Example 3:**

```
**Input:** nums = ["111","011","001"]
**Output:** "101"
**Explanation:** "101" does not appear in nums. "000", "010", "100", and "110" would also be correct.
```

**Constraints:**

* `n == nums.length`
* `1 <= n <= 16`
* `nums[i].length == n`
* `nums[i]` is either `'0'` or `'1'`.
* All the strings of `nums` are **unique**.

## ac

```java
```