[프로그래머스] 게임 맵 최단거리 (BFS) - Java

https://school.programmers.co.kr/learn/courses/30/lessons/1844?language=java 

프로그래머스

 

문제 풀이

import java.util.*;

class Solution {

    static int visited[][];
    static Queue<Node> queue;
    static int dx[] = {0, 1, 0, -1};
    static int dy[] = {1, 0, -1, 0};

    public int solution(int[][] maps) {
        int answer = 0;
        int n = maps.length;
        int m = maps[0].length;

        visited = new int[n][m];
        queue = new LinkedList<>();

        bfs(maps, n, m);
        answer = visited[n - 1][m - 1];

        if (answer == 0) answer = -1;

        return answer;
    }


    public static void bfs(int[][] maps, int n, int m) {
        visited[0][0] = 1;
        queue.add(new Node(0, 0));

        while (!queue.isEmpty()) {
            Node node = queue.poll();

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

                if (nx < 0 || ny < 0 || nx >= n || ny >= m) continue;

                if (visited[nx][ny] == 0 && maps[nx][ny] == 1) {
                    visited[nx][ny] = visited[node.x][node.y] + 1;
                    queue.add(new Node(nx, ny));
                }
            }
        }
    }

}

class Node {
    int x;
    int y;

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