LeetCode:Excel Sheet Column Number

问题描述：

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

思路：

将26进制转为10进制。

代码：

public class Solution {
public int titleToNumber(String s) {
int sum = 0;
for(int i = 0; i < s.length(); i++) {
char  item =  s.charAt(i);
sum = sum * 26 + (item - 64);
}
return sum;
}
}