Given a List of words, return the words that can be typed using letters of alphabet on only one row's of American keyboard like the image below.

 

 

Example 1:

Input: ["Hello", "Alaska", "Dad", "Peace"]Output: ["Alaska", "Dad"]

 

Note:

1. You may use one character in the keyboard more than once.
2. You may assume the input string will only contain letters of alphabet.

大致意思是输入一个数组，找到其中是由同一行字母组成的字符串组成新的数组

思路很简单，使用hashmap存储一个键值对，键是每个字母，值是1，2，3。对于输入的字符串判断每个字符的hashmap的值是否一样即可

public String[] findWords(String[] words) {       ArrayList
     
       list = new ArrayList();            String arr1[] = {"q", "w", "e", "r", "t", "y", "u", "i", "o", "p"};            String arr2[] = {"a", "s", "d", "f", "g", "h", "j", "k", "l"};            String arr3[] = {"z", "x", "c", "v", "b", "n", "m"};            HashMap temp = new HashMap();            for(String s:arr1)            {                temp.put(s, 1);            }             for(String s:arr2)            {                 temp.put(s, 2);            }             for(String s:arr3)            {                 temp.put(s, 3);            }            for(int i=0;i