算法-斐波那契数列

1、了解斐波那契数列，它是这样一个数列：1、1、2、3、5、8、13、21、34、……在数学上，斐波纳契数列以如下被以递归的方法定义：F(1)=1，F(2)=1, F(n)=F(n-1)+F(n-2)（n>=2，n∈N*）。
2、代码实现

def decorator(func):
    def wrapper(*args, **kwargs):
        start_time = time.time()
        func()
        end_time = time.time()
        print("\n")
        print(end_time - start_time)
    return wrapper

def fib_recur(n):
    '''
    递归方法实现
    '''
    if n<=1:
        return n
    return fib_recur(n-1)+fib_recur(n-2)

def fib_loop(n):
    '''
    递推方法实现
    '''
    a,b=0,1
    if n == 0 or n == 1:
        return n
    for i in range(n):
        a,b=b,a+b
    return a

def fib_loop_while(max):
    '''
    生成器实现
    '''
    a, b = 0, 1
    while max > 0:
        a, b = b, a+b
        max -= 1
        yield a

@decorator
def test_001():
    for i in range(1,35):
        print(fib_recur(i),end=",")

@decorator
def test_002():
    for i in range(1,100):
        print(fib_loop(i),end=",")

@decorator
def test_003():
    for i in fib_loop_while(20):
        print(i,end=",")

test_001()
test_002()
test_003()