tvl-depot/scratch/facebook/interview-cake/nth-fibonacci.py

def fib(n):
    cache = (0, 1)
    for _ in range(n):
        a, b = cache
        cache = (b, a + b)
    return cache[0]
Implement a bottom-up fibonacci The bottom-up solution run in O(n) time instead of O(2^n) time, which the recursive solution runs as: ``` def fib(n): return fib(n - 2) + fib(n - 1) ``` Remember that exponential algorithms are usually recursive algorithms with multiple sibling calls to itself. 2020-11-21 15:48:12 +01:00			`def fib(n):`
			`cache = (0, 1)`
			`for _ in range(n):`
			`a, b = cache`
			`cache = (b, a + b)`
			`return cache[0]`