试题名称 算法提高 逃跑的牛 Java（BFS）

import java.util.*;
public class Main{
    static boolean[] vis = new boolean[100005];
    static int n;
    static int k;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        k = sc.nextInt();
        bfs();
    }
    public static void bfs(){
        Queue q = new linkedList<>();
        q.offer(new POS(n,0));
        vis[n] = true;
        while (!q.isEmpty()){
            POS now = q.poll();
            int now_position = now.position;
            int now_time = now.time;
            if(now_position == k){
                System.out.println(now_time);
                break;
            }
            int next_position = now_position+1;
            int next_time = now_time+1;
            if(check(next_position)){
                vis[next_position] = true;
                q.offer(new POS(next_position,next_time));
            }
            next_position = now_position-1;
            next_time = now_time+1;
            if(check(next_position)){
                vis[next_position] = true;
                q.offer(new POS(next_position,next_time));
            }
            next_position = now_position*2;
            next_time = now_time+1;
            if(check(next_position)){
                vis[next_position] = true;
                q.offer(new POS(next_position,next_time));
            }
        }
    }
    public static boolean check(int x){
        if(x >= 0 && x <= 100000 && vis[x] == false){
            return true;
        }
        return false;
    }
}
class POS{
    int position;
    int time;

    public POS(int position, int time) {
        this.position = position;
        this.time = time;
    }
}