算法练习

斐波那契:

def fei(x,a=1,b=1,i=0,li=None):
    i+=1
    if li == None:
        li=[1,1]
    if i == x:
        a,b = b,a+b
        li.append(b)
        return li
    else:
        a,b = b,a+b
        li.append(b)
        return fei(x,a,b,i,li)

结果:

fei(5)
---------------------------
[1, 1, 2, 3, 5, 8, 13]


fei(15)
---------------------------
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597]

---

假POW函数：

def cospow(x,n):
    if n == 1:
        return x
    elif n == 0:
        return 1
    elif x == 0:
        return 0
    elif n<0:
        return 1/(cospow(x,n*-1-1)*x)

    return cospow(x,n-1)*x