349. 两个数组的交集

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        map<int,int>mp1;
         vector<int>ans;
        set<int>st;
        for(auto t:nums1){
            mp1[t]++;
        }
        
        for(auto t:nums2){
            if(mp1[t]!=0){
                if(!st.count(t)){
                    st.insert(t);
                    ans.push_back(t);
                }
                

            }
        }
        return ans;
    }
};