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.

class Solution():
    def lengthOfLastWord(self, s):
        length = 0
        for i in reversed(s):
            if i == ' ':
                if length:
                    break
            else:
                length += 1
        return length


if __name__ == "__main__":
    assert Solution().lengthOfLastWord("Hello World") == 5
    assert Solution().lengthOfLastWord("") == 0