171. Excel Sheet Column Number

题目：

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 

链接： http://leetcode.com/problems/excel-sheet-column-number/

2/20/2017, Java

public class Solution {
    public int titleToNumber(String s) {
        int value = 0;
        char c;
        for (int i = 0; i < s.length(); i++) {
            c = s.charAt(i);
            value = value * 26 + (c - 'A' + 1);
        }
        return value;
    }
}