What the... I neet to drown myself by stuffing my head into toilet..

Genius!

I feel so stupid now than I'm going to drown myself by stuffing my head into the toilet. See you on the other side...

Not a kata issue, then?

Likely code runner server performance issues, check: https://codewars.statuspage.io/

What if there are multiple first characters in string? Then this fails, for example to compare shiftedDiff("fofe","ofef")

The tests do timeout even with the following function: fib(BigInteger n) { return n; }

How do you deal with the timeout problem from there?

The main reson that the problem is ranked 3kyu is that you have to deal with the timeout problem.

I've got the same problem in Java

I'm guessing you're doing it in Java?

EDIT:
When I tested in Java, I also got the same error?

mattc i agree that solution may be inefficiant, but it shouldn't give an error saying submission timed out, if efficiancy is the problem, why don't you add a test case which checks how long call is taking and throw an exception saying taking too long to respond.

I did have an inefficianct solution, which threw an exception saying its taking more than 10000ms when i submit, so i assume if in-efficiancy was still a problem, it should have given me the same error.

Either your solution isn't optimised or it's an error with codewars. There's no need to create an issue over it, you can debug your inputs by printing them. It's important to ntoe you can pass the normal test cases but still have an inefficient solution.

I'm facing the same problem as SithFire, "Submission timed out. Please try again.", All tests are passing, when i try to submit i run into this error.