1.斐波那契数列

#递归法 
def fib(n):
    if n <= 0:
        return 1
    elif n == 1:
        return n
    else:
        return fib(n-1) + fib(n-2)
    
for i in range(0,30):
    print(fib(i), end = ‘ ‘)

#O(1.618^n)

#循环法
def fib_loop(n):
    a, b  = 0, 1
    for i in range(n+1):
        a, b = b, a+b
        return a
    
for i in range(0,30):
    print(fib(i), end = ‘ ‘)
#O(n)