168ExcelSheetColumnTitle.py

"""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 
    ...
Example 1:

Input: 1
Output: "A"
Example 2:

Input: 28
Output: "AB"
Example 3:

Input: 701
Output: "ZY"""

def convertToTitle(self, n):
        """
        :type n: int
        :rtype: str
        """
        s = ''
        while n>0:
            s += chr((n-1)%26 + ord('A'))
            n = (n-1)//26
        return s[::-1]