I am stuck with my solutions for some time. It is not performant enough to pass the tests. I have looked everywhere for guidance but Lambda Calculus implementation of this scale is rarely talked about. I tried testing solutions in chunks and what I found is when I don't include zipWith in the solutions, solutions are fast enough(around 5000ms) to get a result back from server and pass all the tests except zipWith, but when I include zipWith it's just Execution Timed Out. I wonder whether drop and tail or head is the problem as I have to use them for zipWith.

Sorry, I meant cons (head l) ....

Output says "192904397" expected True but got False.
Neither is it a 10 digits nor modulo 11 equals zero, unless I put an X in the end.
Am I missing something here? I found comments that say 9 digits should be correct but the description says otherwise.

I am stuck on def, getting a value out of manad. Any help on this?

Very clever. Could have been more readable if parameters a and b were named something more appropriate.

Clever solution, but it will fail for cases like [7, 7, 1, 2, 3, 4, 5] where there are same numbers at the beginning of an array in "RA".

Hi, just wanted to suggest a test case.
Current test cases lack arrays like [7, 7, 1, 2, 3] where there are two or more same numbers at the beginning of an array in "RA" or "RD"
I have seen some solutions fail that.