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
看成26进制，AA则为 1 * 26 + 1 * 1
BB则为 2 * 26 + 2 * 1
C#代码：
public class Solution { public int TitleToNumber(string s) { char[] ch = s.ToCharArray(); int result = 0; int pro = 1;//每多一位，则是可以看成26进制 for(int i = ch.Count() - 1; i >= 0; i--) { if(i == ch.Count() - 1) { result += (int)ch[i] - ‘A‘ + 1; } else { result += pro * ((int)ch[i] - ‘A‘ + 1); } pro *= 26; } return result; } }
原文：http://www.cnblogs.com/Anthony-Wang/p/5077091.html