[LeetCode] 500. Keyboard Row

轉自LeetCode

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.

<Solution>

想法如下

• 將每個 row 做分群。可以用 set 或是 bit mask，這次使用 bit mask

• 分群 : QWERTYUIOP -> 001，ASDFGHJKL -> 010，ZXCVBNM -> 100

• 將每個字串裡面的字元，對 mask = 111 做 AND，如果最後 mask不為 0，就是要的答案

code 如下

C++(參考解法)

Java