class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> response;
        unordered_map<string, vector<string>> keys;
        if(strs.size() == 0)
            return response;

        for(int i = 0; i < strs.size(); i++) {
            auto current = strs[i];
            sort(current.begin(), current.end());
            keys[current].push_back(strs[i]);
        }

        for(auto k : keys) {
            response.push_back(k.second);
        }
        return response;
 }

};