【leetcode Java】Excel Sheet Column Number

题目如下：

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 

可以看出规律是，如果字符串是ABA的话，26*28+1

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