LeetCode之Keyboard Row

1、题目：

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"]

2、代码实现：

import java.util.ArrayList;
public class Solution {public ArrayList<String> resultList;//检验这个字符串是否全在同一行public boolean check(String s1, String s2) {if (s1 == null) {return false;}for (int i = 0; i < s1.length(); ++i) {if (s2.indexOf(s1.charAt(i)) == -1) {return false;}}return true;}public  String[] findWords(String[] words) {//检验字符串数组是否都为nullif (words == null) {return null;}int length = words.length;String s1 = "qwertyuiop";String s2 = "asdfghjkl";String s3 = "zxcvbnm";resultList = new ArrayList<String>();//判断每次for (int i = 0; i < length; ++i) {String lowerStr = words[i].toLowerCase();if (lowerStr != "") {if (s1.indexOf(lowerStr.charAt(0)) != -1) {if(check(lowerStr, s1))resultList.add(words[i]);}if (s2.indexOf(lowerStr.charAt(0)) != -1) {if(check(lowerStr, s2))resultList.add(words[i]);}if (s3.indexOf(lowerStr.charAt(0)) != -1) {if(check(lowerStr, s3))resultList.add(words[i]);}	}}String[] strArr = new String[resultList.size()];resultList.toArray(strArr);return strArr;}
}