BOJ 1309번 동물원

package BOJ._0119;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class BOJ_1309 {

    static int[][] answer;
    static int mod = 9901;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        answer = new int[n + 1][3];
        solve(n);
    }

    private static void solve(int n) {
        answer[1][0] = 1;
        answer[1][1] = 1;
        answer[1][2] = 1;
        for(int i=2; i<=n; i++){
            answer[i][0] = answer[i-1][0]%mod + answer[i-1][1]%mod + answer[i-1][2]%mod;
            answer[i][1] = answer[i-1][0]%mod + answer[i-1][2]%mod;
            answer[i][2] = answer[i-1][0]%mod + answer[i-1][1]%mod;
        }
        System.out.println((Arrays.stream(answer[n]).sum())%mod);
    }
}