349. Intersection of Two Arrays

class Solution {public:    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {        unordered_set<int> s(nums1.begin(),nums1.end());        vector<int> ret;        for(auto x : nums2)            if(s.erase(x))                ret.push_back(x);        return ret;        /*set<int> temp;        for(auto num : nums1)                temp.insert(num);        set<int> result;        for(auto num : nums2)            if(temp.find(num)!=temp.end()&&result.find(num)==result.end())                result.insert(num);        vector<int> ret(result.begin(),result.end());        return ret;*/    }};