Find how many even Fibonacci numbers are available in the first d numbers.
Consider the following first 14 numbers
1 1 2 3 5 8 13 21 34 55 89 144 233 377 ...
4 of them are even.
Big number is a problem. Instead we can find the regular pattern in which those even and odd numbers appear. Then everything becomes simple and easy.
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.
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