Problem 3095. Return fibonacci sequence do not use loop and condition version 2

Created by Binbin Qi

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203 Solutions
43 Solvers

Last Solution submitted on Nov 26, 2022

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8 Comments

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M.C. on 23 Apr 2015

For some reason, I keep getting test suite errors:
L 3 (C 29-33): Invalid syntax at 'error'. Possibly, a ), }, or ] is missing. L 3 (C 29-33): Invalid syntax at 'error'. Possibly, a ), }, or ] is missing.

Jan Orwat on 23 Apr 2015

Hi M.C., in this problem some of the functions are banned by author. This cause "standard" solutions known from previous fibonacci numbers related problems to fail. Examine your code against functions and operators listed in 1st test.

M.C. on 24 Apr 2015

Thanks Jan. I would have expected to receive the message "No fancy functions!" if was using something I shouldn't be. Here is my solution (which works in my matlab and doesn't appear to have anything "illegal"):
function y = fib(x)
[v,d] = eig([1 1; 1 0]);
M = v*bsxfun(@times, [d(1,1).^(x-1);d(2,2).^(x-1)], v\[1;1]);
y = uint8(M(2,:));
end

M.C. on 24 Apr 2015

Ok, I see - I'm not allowed to use ^. The list of banned functions seems much more restrictive than not using a for or a conditional. Back to the drawing board!

Jan Orwat on 25 Apr 2015

have fun!

Rafael S.T. Vieira on 31 Aug 2020

The problem has way more restrictions than described. We cannot even use round, fix, ceil or floor, which is a pain (almost prohibiting approx. methods). In such cases, It is probably better that the author states what is the method that he is looking for.

Rafael S.T. Vieira on 31 Aug 2020

Btw, stating which method or function to use only makes a problem easier for people that already know it, which means that they are not learning something new. And that is still true regardless of whether people know it or not. Someone that know the required method will try everything they know and will solve the problem, while someone that doesn't know the required method will also try everything, but will be stuck after emptying their options (and may do some research, give up, or cheat*). If we want to estimulate learning (avoiding the unwanted alternatives), revealing the method may help so that people don't give up. Of course, it is also possible to give some tips or a link.

* Cheating is the prefered choice at Cody and probably also in real life.

Dyuman Joshi on 3 Jul 2021

I totally agree with Rafael

Solution Comments

Solution 7782799

1 Comment

1 Comment

Christian Schröder on 7 Oct 2022

This is a cool solution, generally speaking --- but it only passes the test suite because the problem's author's first test, which is supposed to disallow use of the ^ operator, is actually bugged itself.

Solution 6969484

1 Comment

1 Comment

Christian Schröder on 7 Oct 2022

This is an EXCELLENT solution, and taught me about filter(), which I didn't know about before!

Solution 6336142

1 Comment

1 Comment

Dyuman Joshi on 12 Aug 2021

Not bad!

Solution 2069153

1 Comment

1 Comment

David Hill on 25 Dec 2019

Can Cody not handle nested functions?

Solution 2069099

1 Comment

1 Comment

David Hill on 25 Dec 2019

Not sure why this solution is not working. It runs and works when I run it on my matlab.

Solution 599135

1 Comment

1 Comment

Rafael S.T. Vieira on 31 Aug 2020

I won't judge because a lookup table is really tempting when the problem author adds a plethora of restrictions.

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Problem 3095. Return fibonacci sequence do not use loop and condition version 2

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Problem 3095. Return fibonacci sequence do not use loop and condition version 2

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