2019年今日头条机试_JAVA后台岗_第一题

   

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import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

class Node{
    public int x_,y_;
    public int time_;
    public Node(int x,int y,int t){
        x_ = x;
        y_ = y;
        time_ = t;
    }
}

public class Main {

    public static boolean inside(int x,int y,int r,int c){
        if(x>=0&&x<r&&y>=0&&y<c)
            return true;
        return false;
    }

    public static void main(String[] args)
    {
        Integer[][] graph = new Integer[11][11];
        int[][] dir = new int[][]{{-1,0}, {0, 1}, {1, 0},{0,-1}};
        boolean[][] flag = new boolean[11][11];
        int row=0, col=0,total=0,cnt=0;
        Scanner in = new Scanner(System.in);
        Queue<Node> que = new LinkedList<Node>();
        while(in.hasNext()){
            String line = in.nextLine();
            if(line.equals(""))
                break;
            String[] strs = line.split("\ ");
            col = strs.length;
            for(int i=0;i<col;i++) {
                graph[row][i] = Integer.valueOf(strs[i]);
                if(graph[row][i]!=0)
                    total++;
                if(graph[row][i] == 2){
                    flag[row][i] = true;
                    Node node = new Node(row,i,0);
                    que.add(node);
                }
            }
            row++;
        }
        int res = 0;
        while(que.isEmpty() == false){
            Node now = que.poll();
            res = Math.max(res, now.time_);
            cnt++;
            //System.out.println(now.x_+now.y_);
            for(int i=0;i<4;i++){
                int xx = now.x_+dir[i][0];
                int yy = now.y_+dir[i][1];
                if(inside(xx,yy,row,col)&&flag[xx][yy]==false&&graph[xx][yy]==1){
                    flag[xx][yy] = true;
                    que.add(new Node(xx,yy,now.time_+1));
                }
            }
        }
        if(cnt<total)
            System.out.println(-1);
        else if(cnt==total)
            System.out.println(res);
        return ;
    }