Group Anagrams - https://leetcode.com/problems/group-anagrams/description/

gistfile1.txt

class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
      
      if (strs == null || strs.length == 0)
        return new LinkedList<List<String>>();
        
      Map<String, List<String>> superAnagrams = new HashMap<>();
      
      int sLen = strs.length;
      for (String str : strs) {
        // Sort
        char[] asChars = str.toCharArray();
        Arrays.sort(asChars);
        String sortedStr = new String(asChars);
        
        List<String> anagrams = null;
        if (!superAnagrams.containsKey(sortedStr)) {
          anagrams = new LinkedList<String>();
          superAnagrams.put(sortedStr, anagrams);
        } else {
          anagrams = superAnagrams.get(sortedStr);
        }
        anagrams.add(str);
      }
      
      List<List<String>> results = new LinkedList<List<String>>(superAnagrams.values());
      return results;
    }
}