LeetCode 171. 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

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