168. Excel Sheet Column Title

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

Solution:

class Solution(object):
    def convertToTitle(self, n):
        """
        :type n: int
        :rtype: str
        """
        if n <= 0:
            return ''
        chars = []
        while n:
            n -= 1
            chars.append(chr(ord('A') + n % 26))
            n /= 26
        return ''.join(reversed(chars))

Related:

• 171. Excel Sheet Column Number