Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.
If the last word does not exist, return 0.
Note: A word is defined as a character sequence consists of non-space characters only.
Example:
Input: "Hello World"
Output: 5
解题思路：
这题没啥可讲的，直接用Python的内置函数 .split() 分解以空格为分隔符放的字符串，存到列表中，然后返回最后一个单词的长度。
Python实现：
class Solution:
def lengthOfLastWord(self, s):
"""
:type s: str
:rtype: int
"""
sl = s.split()
if len(sl) == 0:
return 0
return len(sl[-1])
a = "Hello World "
b = Solution()
print(b.lengthOfLastWord(a)) # 5