[백준] 2616 소형기관차 - Dynamic Programming / Java

• 문제 링크

2616번: 소형기관차

 

• 풀이 과정

 

• 풀이 코드

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

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));
        StringTokenizer st;

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

        int[] train = new int[n + 1];
        int[] sum = new int[n + 1];
        int[][] dp = new int[4][n + 1];

        st = new StringTokenizer(br.readLine());
        for (int i = 1; i <= n; i++) {
            train[i] = Integer.parseInt(st.nextToken());
            sum[i] = sum[i - 1] + train[i];
        }

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

        for (int i = 1; i < 4; i++) {
            for (int j = i * max; j <= n; j++)
                dp[i][j] = Math.max(dp[i][j - 1], dp[i - 1][j - max] + (sum[j] - sum[j - max]));
        }

        bw.write(String.valueOf(dp[3][n]));
        bw.flush();
    }

}