백준 4179번 불! [ Java ]

4179번: 불!

틀렸을 때 참고한 반례입니다.

글 읽기 - 테스트 케이스

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

public class Main {
    public static void main(String[] args) throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int[] dx = new int[]{1, 0, -1 ,0};
        int[] dy = new int[]{0, 1, 0, -1};
        ArrayList<int[]> FIRE = new ArrayList<>();
        ArrayList<int[]> JIHOON = new ArrayList<>();
        int[] rc = Arrays.stream(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
        int R = rc[0], C = rc[1];
        String[][] field = new String[R][C];
        int[][] Fdist = new int[R][C];
        int[][] Jdist = new int[R][C];
        for (int i=0; i<R; i++) {
            field[i] = br.readLine().split("");
            Arrays.fill(Fdist[i], -1);
            Arrays.fill(Jdist[i], -1);
            for (int j=0; j<C; j++) {
                if (field[i][j].equals("F")) {
                    FIRE.add(new int[]{i, j});
                    Fdist[i][j] = 0;
                }
                if (field[i][j].equals("J")) {
                    JIHOON.add(new int[]{i, j});
                    Jdist[i][j] = 0;
                }
            }
        }

        while(!FIRE.isEmpty()){
            int[] cur = FIRE.remove(0);
            for (int dir=0; dir<4; dir++){
                int nx = cur[1] + dx[dir];
                int ny = cur[0] + dy[dir];
                if (nx<0 || nx>=C || ny<0 || ny>=R) continue;
                if (Fdist[ny][nx]>=0 || field[ny][nx].equals("#")) continue;
                Fdist[ny][nx] = Fdist[cur[0]][cur[1]]+1;
                FIRE.add(new int[]{ny, nx});
            }
        }

        while (!JIHOON.isEmpty()){
            int[] cur = JIHOON.remove(0);
            for (int dir=0; dir<4; dir++){
                int nx = cur[1] + dx[dir];
                int ny = cur[0] + dy[dir];
                if (nx<0 || nx>=C || ny<0 || ny>=R){
                    System.out.print(Jdist[cur[0]][cur[1]]+1);
                    System.exit(0);
                }
                if (Jdist[ny][nx]>=0 || field[ny][nx].equals("#")) continue;
                if (Fdist[ny][nx]!=-1 && Fdist[ny][nx] <= Jdist[cur[0]][cur[1]]+1) continue;
                Jdist[ny][nx] = Jdist[cur[0]][cur[1]] + 1;
                JIHOON.add(new int[]{ny, nx});
            }
        }
        System.out.print("IMPOSSIBLE");
    }
}