题解 | 牛牛学数列6
牛牛学数列6
https://www.nowcoder.com/practice/b6321648517247b2ac2e2f80cbc63ae1
n = int(input())
def shulie(n):
if n <= 0:
return print('请输入正整数')
elif n == 1:
return 0
elif n == 2 or n == 3:
return 1
else:
return shulie(n-3) + 2*shulie(n-2) + shulie(n-1)
print(shulie(n))