This one was created by GPT 4 - not bad hm?

Short, but no bonus points for you i guess ^^

I had the same thought initially, and it was fine for all the tests here.. I switched to a "range 1-9.except.any" style check in the end..

You can do it safer for sure, but i was just lazy and thought that would do the trick for this kata.

It's neat.. The only bit that I think is risky, is assuming the distinct sum is 45. A cruel test that used board numbers 0,2,3,4,5,6,7,8,10 also sums to 45.. How about some powers of 2 approach like .Select(e => 1<<e).Sum() == 1022 ?

My fault - had a Bug in my Test -.-

Nothing is wrong with servers.

Most probably your tests on your Macbook Air are not really good/representative.

I get a timeout every time for my C#-Code.
On my Macbook Air i ran a heavy test: 100 input length, each number between 10 and 30 (random) and ran it 1000x - it took less than a second.

So, what's wrong with your servers?