@Kashfia Rahman Oyshei: your comment was deleted, as it revealed a potential solution. Regarding your solution failing at large values of d, look at other comments to the problem for hints.

it is working in my Matlab

i'm pretty confident of my code but it doesn't work for d>= 100 due to the lack of percision since it surpasses the capability of double and uint64 so you can't test if the number is even.

I think there is a bug in the assertions after 4th one

What's wrong with this?? It's working in matlab for me .

me2

The fibonacci() function is in a toolbox. Only functions in vanilla Matlab are recognized by Cody.

My code works to d=50 and fails on the higher values in the test suite. I think it is a hardware-limited rounding error (?swamping) with very large numbers. When I test eps(fibonacci(100)) on my system, the answer is 6.5 ie my system can not accurately distinguish odd from even at that large a number.

Leo, your theory is correct: The numbers that you're calculating for d>50 are too large to be represented by a 32-bit digit, and won't be calculated correctly for mod(x,2). Think very carefully about the number pattern in the Fibonacci sequence, and see if a pattern emerges.

Indeed, My code works until the d = 50 because it's a large number, so our algorithm is correct we should not worry about it, I think we have succeed in this challenge.

Not a true solution. Would fail if Test Suite were expanded.

Not a general solution. Will fail if Test Suite expanded.