class Solution {
public:
    string hash(string s){

        string res('*',29);
        for(char c:s)
            res[c-97]++;
        return res; 
    }

    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> res;

        unordered_map<string,vector<string>> mp;
        for(int i=0;i<strs.size();i++){
          mp[hash(strs[i])].push_back(strs[i]);
        }
        for(auto v:mp)
            res.push_back(v.second);
        return res;
    }
};