[백준] 4179. 불!

4179. 불!

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Code

package baekjoon;

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

public class 불_4179 {
    static int R, C;
    static char[][] arr;
    static int[][] dist1, dist2;
    static Queue<Pair> queue1, queue2;
    static int[] dr = {-1, 1, 0, 0};
    static int[] dc = {0, 0, -1, 1};
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine(), " ");

        R = Integer.parseInt(st.nextToken());
        C = Integer.parseInt(st.nextToken());

        arr = new char[R][C];
        dist1 = new int[R][C];
        dist2 = new int[R][C];

        for (int i = 0; i < R; i++) {
            String str = br.readLine();
            for (int j = 0; j < C; j++) {
                arr[i][j] = str.charAt(j);
                dist1[i][j] = -1;
                dist2[i][j] = -1;
            }
        }

        queue1 = new LinkedList<>();
        queue2 = new LinkedList<>();

        for (int i = 0; i < R; i++) {
            for (int j = 0; j < C; j++) {
                if (arr[i][j] == 'F') {
                    queue1.add(new Pair(i, j));
                    dist1[i][j] = 0;
                }
                if (arr[i][j] == 'J') {
                    queue2.add(new Pair(i, j));
                    dist2[i][j] = 0;
                }
            }
        }
        //불 bfs
        bfs1();

        //지훈이 bfs
        bfs2();

        System.out.println("IMPOSSIBLE");
    }
    private static void bfs1() {
        while(!queue1.isEmpty()){
            Pair cur = queue1.poll();
            for(int d=0; d<4; d++){
                int nr = cur.x+dr[d];
                int nc = cur.y+dc[d];
                if(nr < 0 || nc < 0 || nr >= R || nc >= C) continue;
                if(dist1[nr][nc] >= 0 || arr[nr][nc] == '#') continue;
                queue1.add(new Pair(nr, nc));
                dist1[nr][nc] = dist1[cur.x][cur.y]+1;
            }
        }
    }
    private static void bfs2() {
        while(!queue2.isEmpty()){
            Pair cur = queue2.poll();
            for(int d=0; d<4; d++){
                int nr = cur.x+dr[d];
                int nc = cur.y+dc[d];
                if(nr < 0 || nc < 0 || nr >= R || nc >= C){
                    System.out.println(dist2[cur.x][cur.y]+1);
                    return;
                }
                if(dist2[nr][nc] >= 0 || arr[nr][nc] == '#' ) continue;
                if(dist1[nr][nc] != -1 && dist1[nr][nc] <= dist2[nr][nc]) continue;
                queue2.add(new Pair(nr,nc));
                dist2[nr][nc] = dist2[cur.x][cur.y]+1;
            }
        }
    }

    static class Pair{
        int x;
        int y;
        public Pair(int x, int y){
            this.x = x;
            this.y = y;
        }
    }
}