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
...
Input: "A" Output: 1
Input: "AB" Output: 28
Input: "ZY" Output: 701
class Solution:
def titleToNumber(self, s: str) -> int:
ret = 0
for c in s:
ret *= 26
ret += ord(c) - 64
return ret