백준: 숨바꼭질(1697)

처음 코드

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

public class Main {
    public static int n, k; //  n: 수빈이 위치, k: 동생 위치
    public static int[] arr = new int[100_001]; // 좌표
    public static boolean[] visit = new boolean[100_001];
    public static int[] col = {1, -1};
    public static Queue<Integer> q = new LinkedList<>();

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());

        n = Integer.parseInt(st.nextToken());
        k = Integer.parseInt(st.nextToken());

        for (int i = 0; i < arr.length; i++) {
            arr[i] = -1;
        }

        bfs(n);
        System.out.println(arr[k]);

    }

    public static void bfs(int num) {
        boolean result = true;
        q.offer(num);
        arr[num] = 0;
        visit[num] = true;

        while (!q.isEmpty()) {
            if (!result) {
                break;
            }
            int nowLocation = q.poll();

            for (int i = 0; i < 2; i++) {
                int port = nowLocation + col[i];
                int port2 = nowLocation * 2;
                // if (port >= 21 || port2 >= 21) {
                //     continue;
                // }

                if (port < 0 || port >= 100_001) {
                    continue;
                }

                if (port2 < 0 || port2 >= 100_001) {
                    continue;
                }


                if (arr[port2] == -1 && !visit[port2]) {
                    // System.out.println(port2);
                    q.offer(port2);
                    visit[port2] = true;
                    arr[port2] = arr[nowLocation] + 1;
                }

                if (arr[port] == -1 && !visit[port]) {
                    q.offer(port);
                    visit[port] = true;
                    arr[port] = arr[nowLocation] + 1;
                }

                if (port == k || port2 == k) {
                    result = false;
                    break;
                }
            }
        }
    } 













}