[BOJ] 1788 피보나치 수의 확장 (JAVA)

https://www.acmicpc.net/problem/1788

1788번: 피보나치 수의 확장

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	
    public static void main(String[] args) throws Exception {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int[] dp = new int[2_000_001];
        dp[1_000_001] = 1;
        for (int i = 1_000_002; i < 2_000_001; i++) {
            dp[i] = (dp[i - 2] + dp[i - 1]) % 1_000_000_000;
        }
        for (int i = 999_999; i >= 0; i--) {
            dp[i] = (dp[i + 2] - dp[i + 1]) % 1_000_000_000;
        }

        int N = Integer.parseInt(br.readLine()) + 1_000_000;

        if (dp[N] == 0) System.out.println(0);
        else if(0 < dp[N]) System.out.println(1);
        else System.out.println(-1);
        System.out.print(Math.abs(dp[N]));

    }
	
}