[java] 백준 4963 섬의 개수

https://www.acmicpc.net/problem/4963

4963번: 섬의 개수

 

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


public class Main {
	static int arr[][];
	static boolean visited[][];
	static int dx[] = {0,0,-1,1,-1,1,-1,1};
	static int dy[] = {-1,1,0,0,1,1,-1,-1};
	static int w,h,nx,ny;
	
	public static void main(String[] args) throws Exception{
	
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		String str = " ";
		
		while( !(str = br.readLine()).equals("0 0")) {
			st = new StringTokenizer(str);
			
			w = Integer.parseInt(st.nextToken());
			h = Integer.parseInt(st.nextToken());
			arr = new int[h][w];
			visited = new boolean[h][w];
			
			for(int i=0; i<h; i++) {
				st = new StringTokenizer(br.readLine());
				
				for(int j=0; j<w; j++) {
					arr[i][j] = Integer.parseInt(st.nextToken());
				}
			}
			
			int cnt =0;
			for(int i=0; i<h; i++) {
				for(int j=0; j<w; j++) {
					
					if(!visited[i][j] && arr[i][j]==1) {
						cnt++;
						DFS(i,j);
					}
				}
			}
			System.out.println(cnt);
		}

		
	}
	
	static void DFS(int x,int y) {
		visited[x][y] = true;
		
		for(int i=0; i<8; i++) {
			nx = dx[i]+x;
			ny = dy[i]+y;
			
			if(nx>=0 && ny>=0 &&nx<h && ny<w) {
				if(!visited[nx][ny] && arr[nx][ny]==1) {
					DFS(nx,ny);
				}
			}
		}
	}
	
	
}