Leetcode 58 Length of Last Word

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.

For example, 
Given s = "Hello World",
return 5.

字符串基本操作

class Solution(object):
    def lengthOfLastWord(self, s):
        return len(s.rstrip().split(' ')[-1])

 然而看了评论之后发现这个才是正解。。。

class Solution(object):
    def lengthOfLastWord(self, s):
        ans, temp = 0, len(s)-1
        while temp >= 0 and s[temp] == ' ':
            temp -= 1
        while temp >= 0 and s[temp] != ' ':
            temp -= 1
            ans += 1
        return ans