[Solved] Given a string columnTitle that represents the column title as appears in an Excel sheet, return its corresponding column number.

Question

Given a string columnTitle that represents the column title as appears 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: columnTitle = "A"
Output: 1

Example 2:

Input: columnTitle = "AB"
Output: 28

Example 3:

Input: columnTitle = "ZY"
Output: 701

Constraints:

• 1 <= columnTitle.length <= 7
• columnTitle consists only of uppercase English letters.
• columnTitle is in the range ["A", "FXSHRXW"].

Python Solution

class Solution:
    def titleToNumber(self, s: str) -> int:
        n=0
        for i in range(len(s)):
            n = 26*n + ord(s[i])-64
        return n