[LintCode] 最后一个单词的长度

class Solution {
public:
/**
* @param s A string
* @return the length of last word
*/
int lengthOfLastWord(string s) {
int len = 0, tail = s.length() - 1;
while (tail >= 0 && s[tail] == ' ') tail--;
while (tail >= 0 && s[tail] != ' ') {
len++;
tail--;
}
return len;
}
};