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# 349. Intersection of Two Arrays

## 1.問題

![](/files/-LKWlsxrXaAvMrQJQQJS)

## 2.想法

## 3.程式碼

```
class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        vector<int> ans;
        map<int, int> cnt;
        for (int i = 0; i < nums1.size(); i++) {
            if (cnt.find(nums1[i]) == cnt.end()) {
                cnt.insert({nums1[i], 1});
            }  
        }
        for (int i = 0; i < nums2.size(); i++) {
            if (cnt.find(nums2[i]) != cnt.end()) {
                ans.push_back(nums2[i]);
                cnt.erase(nums2[i]);
            } 
        }
        return ans;
    }
};
```

## 4.Performance

![](/files/-LKWmAwP8CeYEvcXwaWm)