1748. Sum of Unique Elements

# 1748. Sum of Unique Elements#

## 题目 #

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`

## 解题思路 #

• 简单题。利用 map 统计出每个元素出现的频次。再累加所有频次为 1 的元素，最后输出累加和即可。

## 代码 #

``````package leetcode

func sumOfUnique(nums []int) int {
freq, res := make(map[int]int), 0
for _, v := range nums {
if _, ok := freq[v]; !ok {
freq[v] = 0
}
freq[v]++
}
for k, v := range freq {
if v == 1 {
res += k
}
}
return res
}
``````

Apr 8, 2023