171. Excel Sheet Column Number

Problem:

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 
    ...

Example 1:

Input: "A"
Output: 1

Example 2:

Input: "AB"
Output: 28

Example 3:

Input: "ZY"
Output: 701

Analysis:
Skip
Solution:

class Solution {
    public int titleToNumber(String s) {
        int res = 0, temp = 1;
        for (int i = s.length() - 1; i >= 0; i--) {
            res += (s.charAt(i) - 'A' + 1) * temp;
            temp *= 26;
        }
        return res;
    }
}