1+ package Algorithms .hash ;
2+
3+ import java .util .ArrayList ;
4+ import java .util .Arrays ;
5+ import java .util .HashMap ;
6+ import java .util .List ;
7+ import java .util .Map ;
8+
9+ public class Anagrams {
10+ public List <String >anagrams (String []strs ) {
11+ List <String >ret =new ArrayList <String >();
12+
13+ if (strs ==null ) {
14+ return ret ;
15+ }
16+
17+ HashMap <String ,List <String >>map =new HashMap <String ,List <String >>();
18+
19+ int len =strs .length ;
20+ for (int i =0 ;i <len ;i ++) {
21+ String s =strs [i ];
22+
23+ // Sort the string.
24+ char []chars =s .toCharArray ();
25+ Arrays .sort (chars );
26+ String strSort =new String (chars );
27+
28+ // Create a ArrayList for the sorted string.
29+ if (!map .containsKey (strSort )) {
30+ map .put (strSort ,new ArrayList <String >());
31+ }
32+
33+ // Add a new string to the list of the hashmap.
34+ map .get (strSort ).add (s );
35+ }
36+
37+ // go through the map and add all the strings into the result.
38+ for (Map .Entry <String ,List <String >>entry :map .entrySet ()) {
39+ List <String >list =entry .getValue ();
40+
41+ // skip the entries which only have one string.
42+ if (list .size () ==1 ) {
43+ continue ;
44+ }
45+
46+ // add the strings into the list.
47+ ret .addAll (list );
48+ }
49+
50+ return ret ;
51+ }
52+ }