Week1 49. Group Anagrams

public class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
        
         List<List<String>>result = new ArrayList<List<String>>();
         
            HashMap <String, List<String> > map = new HashMap<String, List<String>>();
            
            for(int i=0; i<strs.length; i++){
                
             char[] arr = strs [i].toCharArray();
             
             Arrays.sort(arr);
             String key = new String(arr);
             
             if(!map.containsKey(key)){
                 
             map.put (key, new ArrayList<String>());
            }
            
             map.get (key).add(strs[i]);
            }
             
             for(Map.Entry<String, List<String>> entry : map.entrySet()) {
             String key = entry.getKey();
             List<String> value = entry.getValue();
             result.add(value);
            }
            
              return result;
        }
}