题目

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.

分析

这题比较简单，直接从后往前扫描，首先跳过末尾空格，然后统计碰到第一个空格或者到达开头时所经过的字母个数即可。

实现

class Solution {
public:
    int lengthOfLastWord(string s) {
        int ans=0, i=s.size()-1;
        while(i>=0 && s[i]==' ') i--;
        for( ; i>=0; i--){
            if(s[i]==' ') break;
            ans++;
        }
        return ans;
    }
};

思考

无