058 Length of Last Word.py

'''
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(object):
    def lengthOfLastWord(self, s):
        """
        :type s: str
        :rtype: int
        """
        length = len(s)
        index = length - 1
        count = 0
        while index >= 0 and s[index] == " ":
            index -= 1
        while index >= 0 and s[index] != " ":
            index -= 1
            count += 1
        return count


if __name__ == "__main__":
    assert Solution().lengthOfLastWord("       ") == 0
    assert Solution().lengthOfLastWord("  a") == 1
    assert Solution().lengthOfLastWord("  drfish  ") == 6