• set a HashMap.
  • The key is string with letters in lexicographic order.
  • The value is index of list containing anagrams in an ArrayList.

Implementation

public class Solution {    public List
    
     
      > groupAnagrams(String[] strs) {        Arrays.sort(strs);        List
      
       
        > result = new ArrayList
        
         
          >(); HashMap
          
            map = new HashMap
           
            (); for (int i = 0; i < strs.length; i++) { char[] e = strs[i].toCharArray(); Arrays.sort(e); String element = String.valueOf(e); if (map.containsKey(element)) { result.get(map.get(element)).add(strs[i]); } else { ArrayList
            
              list = new ArrayList
             
              (); list.add(strs[i]); result.add(list); map.put(element, result.size() - 1); } } return result; }}