Length of Last Word leetcode

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.

第一种方法是把string按照" " 分成string[] 返回最后一个
第二种方法是维护一个count 从后面往前数遇到第一个空格为止,返回count值 如果count为0 说明最后一个字符是空格 继续往前数一个string 

public class Solution {
    public int lengthOfLastWord(String s) {
        String[] tem = s.split(" ");
        if (tem.length == 0 || tem == null) {
            return 0;
        }
        return tem[tem.length - 1].length();
    }
}
public class Solution {
    public int lengthOfLastWord(String s) {
        if (s.length() == 0 || s == null) {
            return 0;
        }
        int count = 0;
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) != ' ') {
                count++;
            }
            if (s.charAt(i) == ' ' && count != 0) {
                return count;
            }
        }
        return count;
    }
}