题目：
Input: "the sky is blue", Output: "blue is sky the".
几种方式：python的reversed方法；或者实现reversed；再或者实现上述方法涉及的split方法。
代码：三种方式
class Solution:
def func0(self , s):
return ' '.join(reversed(s.split(' ')))
def func1(self , s): # 实现reversed
new_s = ''
s_list = s.split(' ')
while s_list:
new_s += '{} '.format(s_list.pop(-1))
return new_s
def func2(self , s): # 实现split
new_s = ''
lo = hi = len(s) - 1
for i in range(len(s)-1 , -1 , -1):
lo -= 1
if s[i] == ' ':
new_s += '{} '.format(s[lo+2:hi+1])
hi = i-1
if lo != hi:
new_s += '{} '.format(s[lo + 1:hi + 1])
return new_s
a = "the sky is blue"
s = Solution()
print(s.func0(a))
print(s.func1(a))
print(s.func2(a))
输出：
blue is sky the blue is sky the blue is sky the
