leetcode 49: 字母异位词分组

std::vector<std::vector<std::string>> groupAnagrams(std::vector<std::string> &strs){
    std::vector<std::vector<std::string>> sss;
    std::map<std::string,int> m;
    std::string s="";
    int c=0;
    for(int i=0;i<strs.size();i++){
        s=strs[i];
        std::sort(s.begin(),s.end());
        if(m.find(s)==m.end()){
            m[s]=c;
            ++c;
            sss.push_back(std::vector<std::string>{});
        }    
        sss[m[s]].push_back(strs[i]);
    }
    return sss;
}