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

难度：easy

题目：

给定字符串包含大小写字母和空格，返回最后一个单词的长度。

如果最后一个单词不存在，则返回0.

Runtime: 3 ms, faster than 62.11% of Java online submissions for Length of Last Word.

Memory Usage: 21.5 MB, less than 96.23% of Java online submissions for Length of Last Word.

public class Solution {
    public int lengthOfLastWord(String s) {
        if (null == s || s.trim().isEmpty()) {
            return 0;
        }
        s = s.trim();
        int wordLength = 0;
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == ' ') {
                return wordLength;
            } else {
                wordLength++;
            }
        }
        
        return wordLength;
    }
}