[백준] 포도주 시식 (2156번 JAVA) (!) / 401 - 다이나믹 프로그래밍 1 (연습)

[백준] 포도주 시식 (2156번 JAVA) (!) / 401 - 다이나믹 프로그래밍 1 (연습)

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[접근 방법]

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.*;

public class Main{

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

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int N = Integer.parseInt(br.readLine());

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

        int[] DP = new int[N+1];
        DP[1] = arr[1];
        if (N > 1) {
            DP[2] = arr[1] + arr[2];
        }
        for(int i=3; i<=N; i++) {
            DP[i] = Math.max( DP[i-1], Math.max( DP[i-2] + arr[i] , DP[i-3] + arr[i-1] + arr[i]));
        }
        /*
        0 1 2 3
        X X O X         // DP[i-1]
        X O X O         // DP[i-2] + arr[i]
        O X O O         // DP[i-3] + arr[i-1] + arr[i]
        */
        
        bw.write(DP[N] + "\n");
         
        bw.flush();
        bw.close();
    }
}

 

0 1 2 3 (번째)
X X O X         // DP[i-1]
X O X O         // DP[i-2] + arr[i]
O X O O         // DP[i-3] + arr[i-1] + arr[i]

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