Leetcode 171. Excel Sheet Column Number-Excel的列名转换为具体的数字AB-＞28,ZY-＞701

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
 

Constraints:

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

package com.string;

/**
 * @Author you guess
 * @Date 2022/4/8 11:09
 * @Version 1.0
 * @Desc Excel的列名转换为具体的数字AB-＞2