캐슬 디펜스 - 17135번

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내 코드

package com.company;

import java.io.*;
import java.util.*;

public class Main {
    static int[][] d = {{-1, 0}, {0, 1}, {0, -1}};
    static int N, M, D;
    static int[][] arr;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());

        N = Integer.parseInt(st.nextToken());
        M = Integer.parseInt(st.nextToken());
        D = Integer.parseInt(st.nextToken());
        arr = new int[N][M];
        int answer = 0;
        for (int i = 0; i < N; i++) {
            st = new StringTokenizer(br.readLine());
            for (int j = 0; j < M; j++) {
                arr[i][j] = Integer.parseInt(st.nextToken());
            }
        }

        for (int i = 0; i < M; i++) {
            for (int j = i + 1; j < M; j++) {
                for (int k = j + 1; k < M; k++) {
                    int x = 0;

                    for (int v = N - 1; v >= 0; v--) {
                        bfs(v, i);
                        bfs(v, j);
                        bfs(v, k);

                        for (int m = 0; m < M; m++) {
                            if (arr[v][m] != 0 && arr[v][m] != 1) {
                                arr[v][m] = 1;
                                x++;
                            }
                        }
                    }
                    answer = Math.max(x, answer);
                }
            }
        }
        System.out.println(answer);
    }

    static void bfs(int x, int y) {
        PriorityQueue<int[]> q = new PriorityQueue<>((o1, o2) -> {
            if (o1[2] == o2[2])
                return o1[1] - o2[1];
            return o1[2] - o2[2];
        });

        q.add(new int[]{x, y, 1});
        boolean[][] visited = new boolean[N][M];
        visited[x][y] = true;

        while (!q.isEmpty()) {
            int[] node = q.poll();

            if (node[2] > D || arr[node[0]][node[1]] == -(x + 1))
                break;

            if (arr[node[0]][node[1]] == 1) {
                arr[node[0]][node[1]] = -(x + 1);
                break;
            }

            for (int[] i : d) {
                int nextX = node[0] + i[0];
                int nextY = node[1] + i[1];

                if (nextX >= 0 && nextY >= 0 && nextX < N && nextY < M && !visited[nextX][nextY]) {
                    q.add(new int[]{nextX, nextY, node[2] + 1});
                    visited[nextX][nextY] = true;
                }
            }
        }
    }
}