Leetcode 49. Alphabetic heterotopic word grouping

Topic delivery ：https://leetcode.cn/problems/group-anagrams/

The code is as follows :

class Solution {
    
   public static List<List<String>> groupAnagrams(String[] strs) {
    
        List<List<String>> result = new ArrayList<>();
        HashMap<String, List<String>> map = new HashMap<>();
        for (String str : strs) {
    
            String[] split = str.split("");
            Arrays.sort(split);
            if (map.containsKey(Arrays.toString(split))) {
    
                List<String> strings = map.get(Arrays.toString(split));
                strings.add(str);
                map.put(Arrays.toString(split), strings);
            } else {
    
                List<String> strings = new ArrayList<>();
                strings.add(str);
                map.put(Arrays.toString(split), strings);
            }
        }

        Set<String> keys = map.keySet();
        for (String key : keys) {
    
            List<String> strings = map.get(key);
            result.add(strings);
        }
        return result;
    }
}