vjudge domino covering

Link to the original question: https://vjudge.net/contest/331993#problem/B

 

In a rectangular grid of 2 * N, with a 1 * 2 domino filled squares.

Q. How many different methods of arrangement.

For example: 2 * 3 grid, a total of three different discharge methods. (Due to the large number of programs, only the output Mod 10 ^ 9 + 7) is

Input Input N (N <= 1000) Output Output Number Mod 10 ^ 9 + 7Sample Input

3

Sample Output

3

 

 

 

#include<bits/stdc++.h>
using namespace std;
int a[10005];
const int mod=1e9+7;
int main(){
    a[1]=1,a[2]=2;
    int n;
    cin>>n;
    for(int i=3;i<=n;i++){
        a[i]=(a[i-1]+a[i-2])%mod;
    }
    cout<<a[n];
    return 0;
}