LeetCode习题笔记——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.
Example:

Input: "Hello World"
Output: 5

这个题就很简单了，既然说是要最后一个单词的长度，就从后面开始遍历，从结尾第一个不为空格字符串开始计算，然后遇到空格结果并输出结果即可。
class Solution {
public:
int lengthOfLastWord(string s) {
int end = s.size() - 1;
int res = 0;
while (end >= 0 && s[end] == ' ')
--end;
while (end >= 0 && s[end] != ' ') { //注意要>=0,保证遍历到每一个字符
end--;
res++;
}
return res;
}
};