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.

Example:

Input: "Hello World"
Output: 5

 AC code:

class Solution {
public:
    int lengthOfLastWord(string s) {
        int tail = s.length() - 1;
        int len = 0;
        while (tail >= 0 && s[tail] == ' ') tail--;
        while (tail >= 0 && s[tail--] != ' ') len++;
        return len;
    }
};

Runtime: 0 ms, faster than 100.00% of C++ online submissions for Length of Last Word.