LeetCode: 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.

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

For example:

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

题目解析：以26为一个进制，进行叠加即可。

源代码：

int titleToNumber(char* s) {    int len = strlen(s);    int res = 0;    for (int i = 0; i < len; ++i) {        res *= 26;        res += s[i] - 'A' + 1;    }        return res;    }