当基本情况执行时，它会打印值但返回 None

Question

''#the 代码需要在递归终止时执行基本情况时返回接收方的值， import math days = int(input()) def adv(days,recipient,likes,depth): depth+=1 print(" "*depth + "adv({},{})at day {} and likes are {}".format(days-4,recipient,days,likes)) days -= 1 if days == 0: #print(recipient) print(likes) #print(" "*depth + "adv({},{})at day {} and likes are {}".format(days-4,recipient,days,likes)) 这里返回接收方' 返回收件人 还： 喜欢=喜欢+数学地板(收件人/2( ADV(天，数学地板(收件人/2(*3，喜欢，深度(

#the 变量 a 应该接收接收者的值，但

a= adv(天+1,5,0,1(

打印(a(

它返回无

Answer 1

这是因为这是一个递归函数，但是当它从自身内部调用时，你不会返回调用。相反，当从自身内部调用时，最里面的返回值将被丢弃，而 None 将被传递并由原始调用返回。你可以这样修复它：

import math
days = int(input())
def adv(days,recipient,likes,depth):
    depth+=1
    print(" "*depth + "adv({},{})at day {} and likes are {}".format(days-4,recipient,days,likes))
    days -= 1
    if days == 0:
        return recipient
    else:
        likes =likes+ math.floor(recipient/2)
        return adv(days,math.floor(recipient/2)*3,likes,depth) #<------
a= adv(days+1,5,0,1)
print(a)

输出：

5
  adv(2,5)at day 6 and likes are 0
   adv(1,6)at day 5 and likes are 2
    adv(0,9)at day 4 and likes are 5
     adv(-1,12)at day 3 and likes are 9
      adv(-2,18)at day 2 and likes are 15
       adv(-3,27)at day 1 and likes are 24
27