//hashmap implement with STLclass Solution {public:    vector<vector<string>> groupAnagrams(vector<string>& strs) {       // sort(strs.begin(),strs.end());         //sort all the element        map<string,vector<string>>hashmap;        for(vector<string>::iterator it=strs.begin();it!=strs.end();it++)        {            string str=*it;            sort(str.begin(),str.end());            hashmap[str].push_back(*it);     //hashmap;        }        vector<vector<string>>re;        for(map<string,vector<string>>::iterator    it=hashmap.begin();it!=hashmap.end();it++)     //each group with the same key             re.push_back(it->second);        return re;    }};