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.

题目描述：就是输入字符串，然后就是把对应的字符串添加成数字，就是26个字母为一个组合，进行组合，然后输出。

代码实现：

class Solution {
public:
    int titleToNumber(string s) {
        int sum=0;
        int tmp=0;
        for(int i=0;i<s.size();i++)
        {
            tmp=s[i]-'A'+1;
            sum=sum*26+tmp;
        }
        return sum;
    }
};