# Excel Column Number

Posted: 25 Jul, 2020
Difficulty: Easy

## PROBLEM STATEMENT

#### You have been given a 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
...
``````
##### Input Format
``````The only line of input contains a string S i.e. column title
``````
##### Constraints:
``````1 <= |S| <= 10
Input contains only uppercase English Alphabet letters

Time Limit : 1 sec
``````
##### Output Format
``````The only line of output will print the column number corresponding to given column title
`````` Approach 1

The process is very much similar to binary to decimal conversion. In this case, the base of the given system is to be taken as 26. Also, in this system 1 is represented as ‘A’, 2 is represented as ‘B’ and so on till 26 is represented as ‘Z’

For example-

CDA can be converted as 3*26*26 + 4*26 + 1

= 26(3*26 + 4) + 1

= 26(0*26 + 3*26 + 4) + 1

AB can be converted as  1*26 + 2