[알고리즘] 백준 - 2579 (계단 오르기) / 자바

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


class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		int dp[] = new int[n + 1];
		int arr[] = new int[n + 1];

		for (int i = 1; i <= n; i++) {
			arr[i] = Integer.parseInt(br.readLine());
		}

		dp[1] = arr[1];
		if (n >= 2)
			dp[2] = dp[1] + arr[2];

		for (int i = 3; i <= n; i++) {
			dp[i] = Math.max(dp[i - 2] + arr[i], dp[i - 3] + arr[i - 1] + arr[i]);
		}

		System.out.println(dp[n]);

	}

}