题解 | 牛牛学数列6
牛牛学数列6
https://www.nowcoder.com/practice/b6321648517247b2ac2e2f80cbc63ae1
n = int(input())
if n==1:
print(0)
elif n==2 or n==3:
print(1)
else:
dp = [0]*(n+1)
dp[1], dp[2], dp[3] = 0, 1, 1
for i in range(4,n+1):
dp[i] = dp[i-3]+2*dp[i-2]+dp[i-1]
print(dp[-1])
