백준 14940번: 쉬운 최단거리

 

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

public class Main {
    static int n, m;
    static int[][] map;
    static int[][] distance;
    static boolean[][] visited;
    static int[] dx = {1, -1, 0, 0};
    static int[] dy = {0, 0, 1, -1};

    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 = new StringTokenizer(br.readLine());
        n = Integer.parseInt(st.nextToken());
        m = Integer.parseInt(st.nextToken());

        map = new int[n][m];
        distance = new int[n][m];
        visited = new boolean[n][m];

        Queue<int[]> queue = new LinkedList<>();
        int targetX = 0, targetY = 0;

        for (int i = 0; i < n; i++) {
            st = new StringTokenizer(br.readLine());
            for (int j = 0; j < m; j++) {
                map[i][j] = Integer.parseInt(st.nextToken());
                if (map[i][j] == 2) {
                    targetX = i;
                    targetY = j;
                }
                if (map[i][j] == 0) {
                    distance[i][j] = 0;
                } else {
                    distance[i][j] = -1;
                }
            }
        }

        queue.add(new int[]{targetX, targetY});
        visited[targetX][targetY] = true;
        distance[targetX][targetY] = 0;

        while (!queue.isEmpty()) {
            int[] current = queue.poll();
            int x = current[0];
            int y = current[1];

            for (int d = 0; d < 4; d++) {
                int nx = x + dx[d];
                int ny = y + dy[d];

                if (nx >= 0 && ny >= 0 && nx < n && ny < m) {
                    if (map[nx][ny] != 0 && !visited[nx][ny]) {
                        queue.add(new int[]{nx, ny});
                        visited[nx][ny] = true;
                        distance[nx][ny] = distance[x][y] + 1;
                    }
                }
            }
        }

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                bw.write(distance[i][j] + " ");
            }
            bw.newLine();
        }

        br.close();
        bw.flush();
        bw.close();
    }
}