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.

思路：
26进制问题，从后向前遍历字符串

Java代码如下：

public class Solution {    public int titleToNumber(String s) {        if("".equals(s)) {            return 0;        }        int carry = 1, sum = 0;        int len = s.length();        for(int i = len - 1; i >= 0; i--) {            int d = s.charAt(i) - 'A' + 1;            d *= carry;             sum += d;            carry *= 26;                    }        return sum;    }}

今天就到这里吧， 拜拜~