349. 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.

答案：

     用set解决

class Solution {
public:
    vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {
        set<int>s1,s2;
        vector<int>s3;
        int n1=nums1.size();
        int n2=nums2.size();
        for(int i=0;i<n1;i++){
            s1.insert(nums1[i]);
        }
        for(int i=0;i<n2;i++){
            s2.insert(nums2[i]);
        }
        set<int>::iterator it1=s1.begin(),it2=s2.begin();
        while(it1!=s1.end()&&it2!=s2.end()){
            if(*it1==*it2){
                s3.push_back(*it1);
                it1++;
                it2++;
            }
            else if(*it1<*it2){
                it1++;
            }
            else{
                it2++;
            }
        }
        return s3;
    }
};