[BOJ] 백준 2193 이친수

[문제]

https://www.acmicpc.net/problem/2193

 

 

[소스 코드]

import java.io.*;
import java.util.*;
public class Main {
    public static void main(String[] args) throws IOException {
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	int n = Integer.parseInt(br.readLine());
    	long[][] dp = new long[n+1][2];
    	dp[1][1] = 1;
    	for(int i=2;i<=n;i++) {
    		dp[i][0] = dp[i-1][0] + dp[i-1][1];
    		dp[i][1] = dp[i-1][0];
    	}
    	System.out.println(dp[n][0]+dp[n][1]);
    }
}