Strings with only special characters, digits, spaces and letters
For input: W3 ar3 in ye@r 2023$$$!äöü ==> expected: <J3 ne3 va lr@e 2023$$$!äöü> but was: <J3 ne3 va lr@e 2023$$$!ogm>

äöü????

already handled here

Enabled in this fork

Oh, ok. I was trying to use regular expressions to get all whitespace, but it didn't work. I'll fix it!

Well, your num_sym list logic is wrong. It contains the letter s and that's why it fails. Your code isn't shifting it.

print('s' in '\s') # True

Mine keeps saying that S should be K... anybody else have this issue?

Is there an issue with one of the test cases? I'm working in Go, but from what I can see in the test results shouldn't "seb`" be "sebz"? Everything else passes fine.

this is already being handled here

Duplicate: https://www.codewars.com/kata/530e15517bc88ac656000716

Well, this one is ancient, so it might be the reason

But it actually is very annoying that kata's difficulty has a very weak correlation with its actual level of difficulty

Free points, lol

This line of your oslution is very wrong and causes a very serious bug: int length = sizeof(str) / sizeof(char);. You need to fix it and change to something what actually calculates the length of the input string.

When you fix it, you still have an off-by-one bug to fix, but this will be, hopefully, an easy part.

Your solution has a serious bug which trips ups the tests. Bugs in your solution are not a kata issue.

The missong quotation mark means that your returned string contains somr unprintable trash at the end. I agree that the message is confusing, but your solution still is most probably incorrect.