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.

For example, 
Given s = "Hello World",
return 5.

solution:代码很简单，但是考虑的情况要很详细。

public class Solution {
    public int lengthOfLastWord(String s) {
        if(s.length()==0||s==null||s==" "){
            return 0;
        }
        int n=s.length();
        while(n>1&&s.charAt(n-1)==' '){
            n--;
        }
        int count=0;      
        while(n>0){
            n--;
            if(s.charAt(n)!=' '){
            count++;
            }else{
                break;
            }
            
        }
        return count;
    }
}