Fibonacci Implementations in python (iterative, recursive, memoized recursive)

fibonacci_implementations.py

def fibonacci_iterative(n):
    if n == 0:
        return 0

    x = 0
    y = 1
    for i in range(1, n):
        z = (x + y)
        (x, y) = (y, z)

    return z
    
def fibonacci_recursive(n):
    return n if n < 2 else fib(n-2) + fib(n-1)
    

def memoize(f):
    cache = {}
    def decorated_function(*args):
        if args in cache:
            return cache[args]
        else:
            cache[args] = f(*args)
            return cache[args]
    return decorated_function

@memoize
def fibonacci_memoized(n):
    return n if n < 2 else fib(n-2) + fib(n-1)

# dynamic programming solution
def fib(n):
   fibValues = [0, 1]
   for i in range(2, n+1):
      fibValues.append(fibValues[i-1] + fibValues[i-2])
   return fibValues[n]