171. 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    AB -> 28 

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

可以把这个字符串想象成26进制数，A-Z代表了1-26，后面只需从第一位依次取出每一位乘以26累加即可。代码如下：

public class Solution {    public int titleToNumber(String s) {        int result = 0;        for (char ch:s.toCharArray()) {            result = result * 26 + (ch - 'A' + 1);        }        return result;    }}