an optimised fibonacci generating algorithm using memoisation

better.py

def better_fib(n):
    if n >= 0 and n <= 1:
        return n
    else:
        fib = [0, 1]
        for i in range(2, n + 1):
            fib.append(fib[i - 1] + fib[i - 2])
        return fib[n]