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.

求最后一个非空单词的长度而已，没什么注意点，直接看代码，理解题目意思就可以了：

1 class Solution { 2 public: 3     int lengthOfLastWord(string s) { 4         int len  = s.length(); 5         if(len == 0) return 0; 6         while(s[len - 1] == ' ') 7             if(len - 1 >= 0) 8                 len--; 9             else10                 return 0;11         len--;12         int lenCount = 0;13         while(s[len] != ' ' && len >= 0){14             lenCount++, len--;15         }16         return lenCount;17     }18 };

 java版本的代码如下所示，倒过来读很容易了：

1 public class Solution { 2     public int lengthOfLastWord(String s) { 3         int i = s.length() - 1; 4         while(i >= 0 && s.charAt(i) == ' ') 5             i--; 6         int end = i+1; 7         while(i >= 0 && s.charAt(i) != ' ') 8             i--; 9         int start = i+1;10         return end - start;11     }12 }