leecode-349

set
class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        unordered_set <int> result_set;
        unordered_set <int> nums_set(nums1.begin(),nums1.end());
        for(int num:nums2){
            if(nums_set.find(num)!=nums_set.end()){
                result_set.insert(num);
            }
        }
        return vector<int>(result_set.begin(),result_set.end());
    }
};
数组法
class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        unordered_set <int> result_set;
        int hash[1001] = {0};
        for(int num:nums1){
            hash[num]++;
        }
        for(int num:nums2){
            if(hash[num]){
                result_set.insert(num);
            }
        }
        return vector<int>(result_set.begin(),result_set.end());
    }
};