[LeetCode349] Intersection of Two Arrays

题目：

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.

分类：Hash Table   Two Pointers  Sort

代码：

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        vector<int> res;
        set<int> hash;
        
        for(auto num : nums1)
            hash.insert(num);
            
        //比较num2与hash中的元素
        for(auto num : nums2)
        {
            auto it = hash.find(num);
            if(it != hash.end())
             {
                 res.push_back(num);
                 hash.erase(num);
             }
        }
        
        return res;
    }
};