Excel Sheet Column Title

Problem: Excel Sheet Column Title

It's apparent that the problem is about convert 10-base numbers into 26-base numbers.

Code in Python:

class Solution(object):
    def convertToTitle(self, n):
        """
        :type n: int
        :rtype: str
        """
        # letters = "Z" + string.ascii_uppercase[:25]
        # if n <= 26:
        #     return letters[n % 26]
        # else:
        #     return self.convertToTitle((n - 1) / 26) + letters[n % 26]

        letters = "Z" + string.ascii_uppercase
        res = ""
        while n > 26:
            res = letters[n % 26] + res
            n = (n-1) / 26
        res = letters[n] + res
        return res

The commented part is recursive solution.