字母异位词分组

 public static List> groupAnagrams(String[] strs) {
        HashMap> map = new HashMap<>();
        for(int i = 0;i < strs.length;i++){
            String str = strs[i];
            char[] chars = str.toCharArray();
            Arrays.sort(chars);
            List list = map.getOrDefault(new String(chars),new ArrayList<>());
            list.add(str);
            map.put(new String(chars),list);
        }
        return new ArrayList>(map.values());
    }