Easy to Understand for beginners || c++
class Solution {\npublic:\n    vector intersection(vector>& a) {\n        unordered_mapmp;\n        for(int i=0;i<a.size();i++)\n        {\n            for(int 
class Solution {\npublic:\n    vector<int> intersection(vector<vector<int>>& a) {\n        unordered_map<int,int>mp;\n        for(int i=0;i<a.size();i++)\n        {\n            for(int j=0;j<a[i].size();j++)\n            {\n                mp[a[i][j]]++;\n            }\n        }\n        vector<int>res;\n        for(auto it :mp)\n        {\n            if(it.second ==a.size())\n            {\n                res.push_back(it.first);\n            }\n                \n        }\n        sort(res.begin(),res.end());\n        return res;\n    }\n};
['C']