leetcode 171

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 

从A到Z依次代表从1到26，按照26进制进位。
代码如下：

 class Solution {
 public:
     int titleToNumber(string s) {
         int n = s.length();
         int m = n;
         int result = ;
         if(n == )
         {
             return ;
         }
         result = (int)s[m-];
         result -= ;
         for(int i = ; i < n+; i++)
         {
             m--;
             if(m == )
             {
                 return result;
             }
             int p = ;
             for(int j = ; j < i; j++)
             {
                 p *= ;
             }
             int re = (int)s[m-];
             re -= ;
             result = result + re * p;
         }
         return result;
     }
 };