Using Linq is adhering to KISS. Yes Linq has performance issues (though often overstated and it does get better with each iteration of .Net) but in 99% of use cases Linq won't be your performance bottleneck and if it is then you can just not use it in those cases.

The advantage of Linq is easier to write/read code. It is far more concise without losing any readability (assuming everyone is passingly familiar with the syntax).

I don't know why you are so enthusiastic about Linq. It sucks (at least for every kata I've seen here thus far).

It is horribly slow, yet people keep using it like it is somehow some godsend. It's allowing people to make horrendous code while they think it's somehow special. More like special-ed...

It's lazy, crappy code...kata after kata. People seem to have forgotten KISS

Not a kata issue, they have the same nested structure, not the same items: sameStructureAs.

"removed"? Do you mean "Retired" or "Draft"?

once I finish the test cases should I publish the kata?

Yeah, just make sure everything is all right, and you can read this

Most python solutions here are without regex.

It comes from the quadratic equation! The 8 * t comes from the 4ac part of it.

hahaha

but it helped me understand what they did lmao

Because you check if the final length is 26, ie. the length of the alphabet.

Run your method with Linq implementation ten times for n=50_000_000 and you will see why :) Linq-based solutions usually call for O(n) solutions. The kata can be solved in O(1). Why run a loop n times when you can solve the problem witohut a loop?

why shouldn't it?

Your kata has been auto-retred because of low satisfaction rating it collected from users trying to solve it. I have not solved it so I do not know exactly what was the problem, but I believe some hints can be found in comments. Additionally, if you want to create a kata and ensure its good quality, you can read following information:

• Documentation on Content Authoring, which is still work in progress, but quality guidelines are more or less stable and conforming to them should help a kata a lot,
• Creating a kata tutorial, which is not published yet and still in progress, but might be useful. I personally don't like it though,
• Recently published tutorial for creating a kata in JS, C or Python (with other languages slowly incoming).

You can't fix it and it's gone

...except it should not be used in this kata.