1748. Sum of Unique Elements

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

这题只要计数就可以了，假如出现了2次，那么把之前加上去的删掉即可。

class SumofUniqueElements : public Solution {
public:
    void Exec() {

    }
    int sumOfUnique(vector<int>& nums) {
        int counters[101] = {0}, sum = 0;
        for (auto v : nums) {
            counters[v]++;
            if (counters[v] == 1) {
                sum += v;
            } else if (counters[v] == 2) {
                sum -= v;
            }
        }
        return sum;
    }
};