58. 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

思路

比较简单，求最后一个字符的长度，先得到最后一个非空字符的位置，再得到最后一个词前面一个空格的位置，两个位置的index值相减即得到最后一个词的位置。

代码

class Solution {
public:
    int lengthOfLastWord(string s) {
        int end = s.find_last_not_of(' ');
        return end == string::npos ? 0 : (end - s.find_last_of(' ', end));
    }
};