leetcode 58:Length of Last Word

题目：

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.

思路：

额，这题比较简单，从最后一个元素开始往前扫描就行啦，刚开始跳过空格。

实现：

class Solution {
public:
	int lengthOfLastWord(string s) {
		int size = s.size();
		int i = size-1;
		while (i >= 0 && s[i] == ' ') --i;
		if (i < 0) return 0;
		int j = i;
		for (; j >= 0 && s[j] != ' '; --j){}
		return (i-j);
	}
};