題目原址

題目描述

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

解題思路

這個是一個成指數增長的數列。

AC程式碼

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