0350_Intersection_of_Two_Arrays_II.cpp

#pragma GCC optimize("Ofast","inline","ffast-math","unroll-loops","no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native","f16c")
auto init = []()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    return 'c';
}();
class Solution {
public:
    vector<int> intersect(vector<int>& nums1, vector<int>& nums2) {
        vector<int> res;
        unordered_map<int, int> mp;
        for(int i: nums1){
            mp[i]++;
        }
        for(int i: nums2){
            if(mp[i]>0){
                res.push_back(i);
                mp[i]--;
            }
        }
        return res;
    }
};