19.2.9 [LeetCode 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

class Solution {
public:
    int lengthOfLastWord(string s) {
        int idx = s.rfind(' ');
        if (idx == s.npos)
            return s.length();
        if (idx == s.length() - 1) {
            s.erase(s.length() - 1);
            return lengthOfLastWord(s);
        }
        return s.length() - idx - 1;
    }
};

主要需要细心，考虑问题全面