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
public class Solution {    public int titleToNumber(String s) {        int sum = 0;    if(s.length()==0||s==null)    return 0;    else    {    char[] cc = s.toCharArray();    int len = cc.length;    for(int i = len-1 ; i>=0 ; i--)    {         sum = (int) (sum+(cc[len-i-1]-'A'+1)*Math.pow(26, i));    }        }    return sum;    }}