Leetcode 349. Intersection of Two Arrays

 1 class Solution {
 2 public:
 3     vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
 4         set<int> s1, s2;
 5         for(int i = 0; i < nums1.size(); i++){
 6             s1.insert(nums1[i]);
 7         }
 8         
 9         for(int i = 0; i < nums2.size(); i++){
10             if(s1.find(nums2[i]) != s1.end())
11                s2.insert(nums2[i]);
12         }
13         vector<int> v;
14         for(set<int>::iterator it = s2.begin(); it != s2.end(); it++){
15             v.push_back(*it);
16         }
17         return v;
18     }
19 };