leetcode 350

 1 class Solution {
 2 public:
 3     vector<int> intersect(vector<int>& nums1, vector<int>& nums2) {
 4         map<int,int>p_map;
 5         vector<int>p_vec;
 6         for(int i=0;i<nums1.size();i++) 
 7         p_map[nums1[i]]++;
 8         for(int i=0;i<nums2.size();i++) {
 9            p_map[nums2[i]]--;
10            if(p_map[nums2[i]]>=0) 
11                 p_vec.push_back(nums2[i]);
12         }
13         return p_vec;
14     }
15 };