[leetcode]349.Intersection of Two Arrays

Posted 2020-07-09

Given two arrays, write a function to compute their intersection.

Example:
Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2].

Note:

• Each element in the result must be unique.
• The result can be in any order.

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Solution:

 1 vector<int> intersection(vector<int>& nums1, vector<int>& nums2) 
 2     {
 3         unordered_set<int> htable;
 4         unordered_set<int> htmp;
 5         vector<int> ret;
 6         
 7         for (int i = 0; i < (int)nums1.size(); i++)
 8             htable.insert(nums1[i]);
 9         
10         for (int i = 0; i < (int)nums2.size(); i++)
11             if (htable.find(nums2[i]) != htable.end())
12                 htmp.insert(nums2[i]);
13         
14         for (auto it = htmp.begin(); it != htmp.end(); ++it)
15             ret.push_back(*it);
16         
17         return ret;
18     }