349 intersection of two Arrays the intersection of two arrays

Given two arrays, write a function to calculate the intersection of them.
Example:
Given num1= [1, 2, 2, 1], nums2 = [2, 2], return [2].
Tips:
Each element in the result must be unique.
We can not consider the order of the output results.
See: https://leetcode.com/problems/intersection-of-two-arrays/description/
C++:

Class Solution {public:    vector<int> intersection (vector<int>& nums1, vector<int>& NUMS2) {        set<int> s (nums1.begin (), Nums1.end ()), res;        for (auto Num:nums2)        {            if (S.count (num))            {                res.insert (num);            }        }        Return vector<int> (Res.begin (), Res.end ());    };

Reference: https://www.cnblogs.com/grandyang/p/5507129.html

349 intersection of two Arrays the intersection of two arrays