3.Keyboard Row

 1     public String[] findWords(String[] words) {
 2         String[] tmp = new String[]{"qwertyuiop","asdfghjkl","zxcvbnm"};
 3         Map<Character,Integer> map = new HashMap<Character,Integer>();
 4         for(int i=0;i<tmp.length;i++)
 5         {
 6             char[] chars = tmp[i].toCharArray();
 7             for(char a:chars)
 8                 map.put(a,i);
 9         }
10         
11         List<String> result = new ArrayList<String>();
12         for(int i=0;i<words.length;i++)
13         {
14             String str = words[i].toLowerCase();
15             int index = map.get(str.charAt(0));
16             boolean flag = true;
17             for(char a:str.toCharArray())
18             {
19                 if(map.get(a) != index)
20                     flag = false;
21             }
22             if(flag)
23                 result.add(words[i]);
24         }
25         return result.toArray(new String[0]);
26         
27     }