public class Solution
extends Object
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"]`.