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

解题思路：

JAVA实现如下：

    public int titleToNumber(String s) {

       int res=0;

	   for(int i=0;i<s.length()-1;i++){

		   res+=s.charAt(i)-'A'+1;

		   res*=26;

	   }

	   return res+s.charAt(s.length()-1)-'A'+1;

    }