# 1748. Sum of Unique Elements

<https://leetcode.com/problems/sum-of-unique-elements>

## Description

You are given an integer array `nums`. The unique elements of an array are the elements that appear **exactly once** in the array.

Return *the **sum** of all the unique elements of* `nums`.

**Example 1:**

```
**Input:** nums = [1,2,3,2]
**Output:** 4
**Explanation:** The unique elements are [1,3], and the sum is 4.
```

**Example 2:**

```
**Input:** nums = [1,1,1,1,1]
**Output:** 0
**Explanation:** There are no unique elements, and the sum is 0.
```

**Example 3:**

```
**Input:** nums = [1,2,3,4,5]
**Output:** 15
**Explanation:** The unique elements are [1,2,3,4,5], and the sum is 15.
```

**Constraints:**

* `1 <= nums.length <= 100`
* `1 <= nums[i] <= 100`

## ac

```java
```