https://leetcode.com/problems/top-k-frequent-elements/description/
Given a string s consisting of words and spaces, return the length of the last word in the string.
A word is a maximal substring consisting of non-space characters only.
Input: s = "Hello World"
Output: 5
Explanation: The last word is "World" with length 5.
Input: s = " fly me to the moon "
Output: 4
Explanation: The last word is "moon" with length 4.
Input: s = "luffy is still joyboy"
Output: 6
Explanation: The last word is "joyboy" with length 6.
1 <= s.length <= 104
s consists of only English letters and spaces ' '.
There will be at least one word in s.