HappyLeetcode38: Excel Sheet Column Number

Related to question Excel Sheet Column Title

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

    A -> 1
    B -> 2
    C -> 3
    ...
    Z -> 26
    AA -> 27
    AB –> 28 

这道题非常之简单，比起原题来简单不少，非常直接，就是一个进制的问题。代码奉上

class Solution {
public:
    int titleToNumber(string s) {
        if (s == "")
            return 0;
        int result = 0;
        int i = 0;
        while (s[i] != '\0')
        {
            result = result * 26 + (s[i]-'A'+1);
            i++;
        }
        return result;
    }
};

 习惯了字符串为空用s=="",实际上用s.empty()更为规范和合适一些。