Given an input string, reverse the string word by word.
Example:
Input: "the sky is blue", Output: "blue is sky the".
Note:
- A word is defined as a sequence of non-space characters.
- Input string may contain leading or trailing spaces. However, your reversed string should not contain leading or trailing spaces.
- You need to reduce multiple spaces between two words to a single space in the reversed string.
代码：
class Solution(object): def reverseWords(self, s): return ''.join([x + ' ' for x in s.split()[::-1]]).strip()