new_contents: """Leetcode 151. Reverse Words in a String
  Medium
  
  Given an input string, reverse the string word by word. 
  
  Example 1:
  Input: "the sky is blue"
  Output: "blue is sky the"
  
  Example 2:
  Input: "  hello world!  "
  Output: "world! hello"
  Explanation: Your reversed string should not contain leading or trailing spaces.
  
  Example 3:
  Input: "a good   example"
  Output: "example good a"
  Explanation: You need to reduce multiple spaces between two words to a single 
  space in the reversed string.
   
  
  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.
  """
  
  class Solution(object):
      def reverseWords(self, s):
          """
          :type s: str
          :rtype: str
          """
          pass
  
  
  def main():
      import time
  
      # Ans: "blue is sky the".
      s = 'the sky is blue'
  
      # Ans: "world! hello".
      s = '  hello world!  '
  
      # Ans: "example good a".
      s = 'a good   example'
  
  
  if __name__ == '__main__':
      main()
  
subject: Add lc151_reverse_words_in_a_string.py