leetcode171 Excel Sheet Column Number

171. Excel Sheet Column Number

Total Accepted: 68083 Total Submissions: 167730 Difficulty: Easy

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;
        string::iterator it = s.end() - 1;
        for (int k = 0; s.begin() != it + 1; --it, ++k)
        {
            ans += (*it - 'A' + 1) * pow(26, k);
        }
        return ans;
    }
};