Excel Sheet Column Number

For example:

    A -> 1
    B -> 2
    C -> 3
    ...
    Z -> 26
    AA -> 27
    AB -> 28 


看成26进制和10进制之间的转换，Excel Sheet Column Title这道题的逆过程

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