题解 | 牛牛学数列6
牛牛学数列6
https://www.nowcoder.com/practice/b6321648517247b2ac2e2f80cbc63ae1?tpId=383&tags=&title=&difficulty=0&judgeStatus=0&rp=0&sourceUrl=
#include <bits/stdc++.h>
using namespace std;
int main() {
int n;
cin>>n;
int a[25];
if(n==1){cout<<0;}
if(n==2||n==3){cout<<1;}
else{
a[1]=0;
a[2]=1;
a[3]=1;
for(int i=4;i<=n;i++){
a[i]=a[i-3]+2*a[i-2]+a[i-1];
}
cout<<a[n];
}
}