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
    ...

Example 1:

Input: "A"
Output: 1

Example 2:

Input: "AB"
Output: 28

Example 3:

Input: "ZY"
Output: 701

Solutions (Python)

1. Solution

class Solution:
    def titleToNumber(self, s: str) -> int:
        ret = 0
        for c in s:
            ret *= 26
            ret += ord(c) - 64
        return ret