An iterative algorithm for Fibonacci numbers

Question

I am interested in an iterative algorithm for Fibonacci numbers, so I found the formula on wiki...it looks straight forward so I tried it in Python...it doesn\'t have a prob

Answer 1

How about this simple but fastest way... (I just discovered!)

def fib(n):
    x = [0,1]
    for i in range(n >> 1):
        x[0] += x[1]
        x[1] += x[0]
    return x[n % 2]

Note! as a result, this simple algorithm only uses 1 assignment and 1 addition, since loop length is shorten as 1/2 and each loop includes 2 assignment and 2 additions.