14-base91-encoding-and-decoding.md

Problem:

BasE91 is a method for encoding binary as ASCII characters. It is more efficient than Base64 and needs 91 characters to represent the encoded data.

The following ASCII charakters are used:

'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
'!#$%&()*+,./:;<=>?@[]^_`{|}~"'

Create two functions that encode strings to basE91 string and decodes the other way round.

b91encode('test') = 'fPNKd'
b91decode('fPNKd') = 'test'
b91decode('>OwJh>Io0Tv!8PE') = 'Hello World!'
b91encode('Hello World!') = '>OwJh>Io0Tv!8PE'

Input strings are valid.

Solution