게임 맵 최단거리

package programmers;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;

public class 게임맵최단거리 {

   private static int[] dy = {-1, 0, 1, 0};
   private static int[] dx = {0, 1, 0, -1};
   private static int[][] checked;

   public static int solution(int[][] maps) {
      init(maps);
      return bfs(maps);
   }

   private static int bfs(int[][] maps) {
      Queue<Pair> q = new LinkedList<>();

      q.add(new Pair(0, 0));
      checked[0][0] = 1;

      while (!q.isEmpty()) {
         Pair p = q.poll();
         addNextPair(maps, q, p);
      }

      return checked[maps.length - 1][maps[0].length - 1];
   }

   private static void addNextPair(int[][] maps, Queue<Pair> q, Pair p) {
      for (int i = 0; i < 4; i++) {
         int ny = p.y + dy[i];
         int nx = p.x + dx[i];
         if (isMap(ny, nx, maps)) {
            continue;
         }
         checked[ny][nx] = checked[p.y][p.x] + 1;
         q.add(new Pair(ny, nx));
      }
   }

   private static boolean isMap(int ny, int nx, int[][] maps) {
      return ny < 0 || ny >= checked.length || nx < 0 || nx >= checked[0].length
         || checked[ny][nx] != -1 || maps[ny][nx] != 1;
   }

   private static void init(int[][] maps) {
      checked = new int[maps.length][maps[0].length];
      for (int i = 0; i < checked.length; i++) {
         Arrays.fill(checked[i], -1);
      }
   }

   private static class Pair {
      int y, x;

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

   public static void main(String[] args) {
      System.out.println(solution(new int[][] {{1, 0, 1, 1, 1}, {1, 0, 1, 0, 1},
         {1, 0, 1, 1, 1}, {1, 1, 1, 0, 1}, {0, 0, 0, 0, 1}}));

      System.out.println(solution(new int[][] {{1, 0, 1, 1, 1}, {1, 0, 1, 0, 1},
         {1, 0, 1, 1, 1}, {1, 1, 1, 0, 0}, {0, 0, 0, 0, 1}}));
   }

}