백준 2156번

원본 : www.acmicpc.net/problem/2156

2156번: 포도주 시식

 

풀이

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Main {

	public static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
	public static BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));

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

		int n = Integer.parseInt(reader.readLine());
		int arr[] = new int[n];
		
		for (int i = 0; i < n ; i++) {
			arr[i] = Integer.parseInt(reader.readLine());
		}
		
		if (n == 1) {
			writer.write(arr[0] + "");
			writer.flush();
			return;
		} else if (n == 2) {
			writer.write(arr[0] + arr[1] + "");
			writer.flush();
			return;
		}
		
		int max[] = new int[n];
		max[0] = arr[0];
		max[1] = arr[1] + arr[0];
		max[2] = maxValue(arr[2] + arr[1], arr[2] + max[0]);
		max[2] = maxValue(max[2], max[1]);
		for (int i = 3; i < n; i++) {
			max[i] = maxValue(arr[i] + arr[i - 1] + max[i - 3], arr[i] + max[i - 2]);
			max[i] = maxValue(max[i], max[i - 1]);
		}
		
		writer.write(maxValueInArray(max) + "");
		
		writer.flush();
	}
	
	public static int maxValue(int a, int b) {
		if (a <= b) {
			return b;
		} else {
			return a;
		}
	}
	
	public static int maxValueInArray(int arr[]) {
		int max = 0;
		for (int i = 0; i < arr.length; i++) {
			if (arr[i] >= max) {
				max = arr[i];
			}
		}
		return max;
	}

}