Given a positive integer, return its corresponding column title as appear in an Excel sheet.
For example:
1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB
class Solution(object): def convertToTitle(self, n): """ :type n: int :rtype: str """ result = ‘‘ while n: result += chr((n-1)%26+65) n = (n-1)/26 return result[-1::-1] #注意逆序
原文：http://www.cnblogs.com/sxbjdl/p/5281381.html