[백준] 21610 마법사 상어와 비바라기 JAVA

문제 링크 : https://www.acmicpc.net/problem/21610

21610번: 마법사 상어와 비바라기

문제에서 하라는 대로 구현하면 된다. 

import java.io.*;
import java.util.*;
public class baekjoon_21610{
    public static int N,M;
    public static int board[][];
    public static int dir[][] = {{0,-1},{-1,-1},{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1}};

    public static class Node{
        int y;
        int x;
        public Node(){}
        public Node(int a,int b){
            y = a;
            x = b;
        }
    }

    public static boolean isBoundry(int y,int x){
        if(y<0 || x<0 || y>=N || x>=N) return false;
        return true;
    }
    public static void move(int direction, int cnt, ArrayList<Node> cloud){
        ArrayList<Node> nextCloud = new ArrayList<Node>();
        cnt %= N;
        boolean visited[][] = new boolean[N][N]; //이전 구름있던 곳 표시
        for(int i=0;i<cloud.size();i++){
            Node c = cloud.get(i);
            int ny = c.y + dir[direction-1][0]*cnt;
            int nx = c.x + dir[direction-1][1]*cnt;
            if(ny<0) ny += N;
            if(nx<0) nx += N;
            if(ny>=N) ny %= N;
            if(nx>=N) nx %=N;
            visited[ny][nx] = true;
            board[ny][nx] +=1;
        }
        for(int i=0;i<N;i++){
            for(int j=0;j<N;j++){
                if(visited[i][j]){
                    int aroundCount = 0;
                    for(int k=1;k<8;k+=2){
                        int ny = i + dir[k][0];
                        int nx = j + dir[k][1];
                        if(!isBoundry(ny,nx))continue;
                        if(board[ny][nx] > 0){
                            aroundCount++;
                        }
                    }
                    board[i][j] += aroundCount;
                }
            }
        }
        for(int i=0;i<N;i++){
            for(int j=0;j<N;j++){
                if(visited[i][j] || board[i][j] <2) continue;
                board[i][j] -= 2;
                nextCloud.add(new Node(i,j));
            }
        }
        cloud.clear();
        for(int i=0;i<nextCloud.size();i++){
            cloud.add(nextCloud.get(i));
        }
    }

    public static void main(String[] args)throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine());
        N = Integer.parseInt(st.nextToken());
        M = Integer.parseInt(st.nextToken());
        board = new int [N][N];
        for(int i=0;i<N;i++){
            st = new StringTokenizer(br.readLine());
            for(int j=0;j<N;j++){
                board[i][j] = Integer.parseInt(st.nextToken());
            }
        }
        ArrayList<Node> cloud = new ArrayList<Node>();
        cloud.add(new Node(N-2,0));
        cloud.add(new Node(N-1,0));
        cloud.add(new Node(N-2,1));
        cloud.add(new Node(N-1,1));
        for(int i=0;i<M;i++){
            st = new StringTokenizer(br.readLine());
            int d = Integer.parseInt(st.nextToken());
            int cnt = Integer.parseInt(st.nextToken());

            move(d,cnt,cloud);
        }
        int ans =0;
        for(int i=0;i<N;i++){
            for(int j=0;j<N;j++){
                ans += board[i][j];
            }
        }
        System.out.println(ans);
    }
}