[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.

For example:

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

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

跟上题一样，26进制到10进制的转换。

 1 class Solution {
 2 public:
 3     int titleToNumber(string s) {
 4         int res = 0;
 5         for (int i = 0; i < s.length(); ++i) {
 6             res *= 26;
 7             res += (s[i] - 'A');
 8             ++res;
 9         }
10         return res;
11     }
12 };