new_contents: Given an input string, reverse the string word by word.
  
  For example,
  Given s = "the sky is blue",
  return "blue is sky the".
  
  Update (2015-02-12):
  For C programmers: Try to solve it in-place in O(1) space.
  
  click to show clarification.
  
  Clarification:
  What constitutes a word?
  A sequence of non-space characters constitutes a word.
  Could the input string contain leading or trailing spaces?
  Yes. However, your reversed string should not contain leading or trailing spaces.
  How about multiple spaces between two words?
  Reduce them to a single space in the reversed string.
  
  class Solution:
      # @param s, a string
      # @return a string
      def reverseWords_1(self, s):
          return ' '.join(s.split()[::-1])
      
      def reverseWords(self, s):
          result = ''
          word = ''
          for char in s:
              if char !=' ':
                  word += char
              elif len(word) > 0:
                  if result == '':
                      result = word + result
                  else:
                      result = word + ' '+ result
                  word = '' # Note: word need to clean to '' here
                  
          if len(word) > 0:  # We need the other check here for the scenario "a" ---> 'a'
              if result != '':
                  result = ' ' + result 
              result = word + result  
          return result 
  
subject: Create Reverse_Words_in_a_String.py