171. Excel Sheet Column Number

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

Solution:

class Solution(object):
    def titleToNumber(self, s):
        """
        :type s: str
        :rtype: int
        """
        num = 0
        for char in s:
            num = num * 26 + ord(char) - ord('A') + 1
        return num

Related:

• 168. Excel Sheet Column Title