# 1133. Largest Unique Number

<https://leetcode.com/problems/largest-unique-number>

## Description

Given an integer array `nums`, return *the largest integer that only occurs once*. If no integer occurs once, return `-1`.

**Example 1:**

```
**Input:** nums = [5,7,3,9,4,9,8,3,1]
**Output:** 8
**Explanation:** The maximum integer in the array is 9 but it is repeated. The number 8 occurs only once, so it is the answer.
```

**Example 2:**

```
**Input:** nums = [9,9,8,8]
**Output:** -1
**Explanation:** There is no number that occurs only once.
```

**Constraints:**

* `1 <= nums.length <= 2000`
* `0 <= nums[i] <= 1000`

## ac

```java
```