58. Length of Last Word (String)

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.

class Solution {
public:
    int lengthOfLastWord(string s) {
        if(s.empty()) return 0;
        
        int len = s.length();
        int i = len - 1;
        int lastLen = 0;
        
        // 去掉空格
        while(s[i] == ' ' && i>=0){
            --i;
        }//while
        while(i >= 0 && s[i] != ' '){
            ++lastLen;
            --i;
        }//while
        return lastLen;
    }
};