171. Excel Sheet Column Number

Easy

Given a string columnTitle that represents the 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: columnTitle = "A"

Output: 1

Example 2:

Input: columnTitle = "AB"

Output: 28

Example 3:

Input: columnTitle = "ZY"

Output: 701

Example 4:

Input: columnTitle = "FXSHRXW"

Output: 2147483647

Constraints:

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