[Leetcode]Excel Sheet Column Number

Given a column title as appear in an Excel sheet, return its corresponding column number.

本质上是一个进制转换问题。

 

1 class Solution {
2 public:
3     int titleToNumber(string s) {
4         int ret = 0;
5         for(int i = 0; i < s.size(); i ++)
6             ret = ret*26 + (s[i]-'A'+1);
7         return ret;
8     }
9 };