函数递归

#字符串反转
def ves(s):
    if s==‘‘:
        return s
    else:
        return ves(s[1:])+s[0]
s=input()
print(s[::-1])
print(ves(s))
‘‘‘
CAVD
DVAC
DVAC
‘‘‘

#汉诺塔
cnt  =0
def hano(n,st,mid,de):
    global cnt
    if n==1:
        print("{}:{}->{}".format(1,st,de))
        cnt+=1
    else:
        hano(n-1,st,de,mid)
        print("{}:{}->{}".format(n,st,de))
        cnt+=1
        hano(n-1,mid,de,st)
hano(3,‘A‘,‘B‘,‘C‘)
print(cnt)
1:A->C
2:A->B
1:C->A
3:A->C
1:B->C
2:B->A
1:C->B
7

#绘制雪花
import turtle
def koh(size,n):
    if n==0:
        turtle.fd(size)
    else:
        for i in[0,60,-120,60]:
            turtle.lt(i)
            koh(size/3,n-1)
def main():
    turtle.setup(600,600)
    turtle.pu()
    turtle.goto(-200,100)
    turtle.pd()
    turtle.pensize(2)
    lev =3
    koh(400,lev)
    turtle.rt(120)
    koh(400,lev)
    turtle.rt(120)
    koh(400,lev)
    turtle.hideturtle()
main()