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67 lines
1.3 KiB
Markdown
67 lines
1.3 KiB
Markdown
# [1748. Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/)
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## 题目
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You are given an integer array `nums`. The unique elements of an array are the elements that appear **exactly once** in the array.
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Return *the **sum** of all the unique elements of* `nums`.
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**Example 1:**
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```
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Input: nums = [1,2,3,2]
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Output: 4
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Explanation: The unique elements are [1,3], and the sum is 4.
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```
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**Example 2:**
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```
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Input: nums = [1,1,1,1,1]
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Output: 0
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Explanation: There are no unique elements, and the sum is 0.
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```
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**Example 3:**
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```
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Input: nums = [1,2,3,4,5]
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Output: 15
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Explanation: The unique elements are [1,2,3,4,5], and the sum is 15.
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```
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**Constraints:**
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- `1 <= nums.length <= 100`
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- `1 <= nums[i] <= 100`
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## 题目大意
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给你一个整数数组 `nums` 。数组中唯一元素是那些只出现 **恰好一次** 的元素。请你返回 `nums` 中唯一元素的 **和** 。
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## 解题思路
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- 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。
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## 代码
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```go
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package leetcode
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func sumOfUnique(nums []int) int {
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freq, res := make(map[int]int), 0
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for _, v := range nums {
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if _, ok := freq[v]; !ok {
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freq[v] = 0
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}
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freq[v]++
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}
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for k, v := range freq {
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if v == 1 {
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res += k
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}
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}
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return res
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}
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``` |