알고리즘 문제 풀이/BOJ

[backjoon]2048(easy)

v 2022. 4. 27. 19:00
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import java.io.*;
import java.util.*;
 
public class Main {
    static int[] orders = new int[5];
    static int[][] map;
    static int N, answer;
 
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        st = new StringTokenizer(br.readLine());
        N = Integer.parseInt(st.nextToken());
        map = new int[N][N];
        for (int i = 0; i < N; i++) {
            st = new StringTokenizer(br.readLine());
            for (int j = 0; j < N; j++) {
                map[i][j] = Integer.parseInt(st.nextToken());
            }
        }
        answer = Integer.MIN_VALUE;
        cases(0);
        System.out.println(answer);
    }
 
    private static void cases(int idx) {
 
        if (idx == 5) {
            int[][] temp = new int[N][N];
            for (int i = 0; i < N; i++) {
                for (int j = 0; j < N; j++) {
                    temp[i][j] = map[i][j];
                }
            }
            int lastIdx = 0;
            int prev = 0;
            for (int order : orders) {
                switch (order) {
                case 0: // 0 위쪽 당기기
                    for (int col = 0; col < N; col++) {
                        lastIdx = 0;
                        prev = 0;
                        for (int row = 0; row < N; row++) {
                            if (temp[row][col] == 0)
                                continue;
                            if (temp[row][col] == prev) {
                                temp[lastIdx - 1][col] = temp[row][col] * 2;
                                temp[row][col] = 0;
                                prev = 0;
                            } else {
                                prev = temp[row][col];
                                temp[row][col] = 0;
                                temp[lastIdx++][col] = prev;
                            }
                        }
                    }
                    break;
                case 1: // 1 아래쪽 당기기
                    for (int col = 0; col < N; col++) {
                        lastIdx = N - 1;
                        prev = 0;
                        for (int row = N - 1; row >= 0; row--) {
                            if (temp[row][col] == 0)
                                continue;
                            if (temp[row][col] == prev) {
                                temp[lastIdx + 1][col] = temp[row][col] * 2;
                                temp[row][col] = 0;
                                prev = 0;
                            } else {
                                prev = temp[row][col];
                                temp[row][col] = 0;
                                temp[lastIdx--][col] = prev;
                            }
                        }
                    }
                    break;
                case 2: // 2 왼쪽 당기기
                    for (int row = 0; row < N; row++) {
                        lastIdx = 0;
                        prev = 0;
                        for (int col = 0; col < N; col++) {
                            if (temp[row][col] == 0)
                                continue;
                            if (temp[row][col] == prev) {
                                temp[row][lastIdx - 1] = temp[row][col] * 2;
                                temp[row][col] = 0;
                                prev = 0;
                            } else {
                                prev = temp[row][col];
                                temp[row][col] = 0;
                                temp[row][lastIdx++] = prev;
                            }
                        }
                    }
                    break;
                case 3: // 3 오른쪽 당기기
                    for (int row = 0; row < N; row++) {
                        lastIdx = N - 1;
                        prev = 0;
                        for (int col = N - 1; col >= 0; col--) {
                            if (temp[row][col] == 0)
                                continue;
                            if (temp[row][col] == prev) {
                                temp[row][lastIdx + 1] = temp[row][col] * 2;
                                temp[row][col] = 0;
                                prev = 0;
                            } else {
                                prev = temp[row][col];
                                temp[row][col] = 0;
                                temp[row][lastIdx--] = prev;
                            }
                        }
                    }
                    break;
                }
            }
 
            for (int row = 0; row < N; row++) {
                for (int col = 0; col < N; col++) {
                    int cur = temp[row][col];
                    answer = Math.max(cur, answer);
                }
            }
 
            return;
        }
 
        for (int i = 0; i < 5; i++) {
            orders[idx] = i;
            cases(idx + 1);
        }
    }
}
cs
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