the best fibonacci implementation?

Sat, 09 Mar 2024 00:00:00 +0000

I’ve been meaning to write about this ever since I came across it in Abelson & Sussman’s wizard book.

I mean, Fibonacci is the classic example of a recursive function. And it’s often just implemented as:

def fib(n):
    if n == 0 or n == 1:
        return 1
    return fib(n-1) + fib(n-2)
print(fib(5))

And while this seems all well and good on the surface, it turns out that this is far from an efficient implementation of the sequence. In particular, we end up computing calls to fib that we’ve already computed. In other words, we perform a lot of redundant computation.

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the best fibonacci implementation?