/* * 49. Group Anagrams * 12.2 by Mingyang */
public List<List<String>> groupAnagrams(String[] strs) { if (strs == null || strs.length == 0) return new ArrayList<List<String>>(); Map<String, List<String>> map = new HashMap<String, List<String>>(); for (String s : strs) { char[] ca = s.toCharArray(); Arrays.sort(ca); String keyStr = String.valueOf(ca); if (!map.containsKey(keyStr)) map.put(keyStr, new ArrayList<String>()); map.get(keyStr).add(s); } return new ArrayList<List<String>>(map.values()); }