[백준:4963] 섬의 개수 - JAVA

import java.util.Scanner;

public class Main {

	static int[][] arr;
	static boolean[][] visit;
	static int w, h;

	private static int dfs(int x, int y) {
		int[] dx = { 0, 0, 1, -1, -1, 1, -1, 1 }, dy = { 1, -1, 0, 0, -1, 1, 1, -1 };

		visit[x][y] = true;
		for (int i = 0; i < dx.length; i++) {
			int xx = dx[i] + x, yy = dy[i] + y;
			if (xx > 0 && yy > 0 && xx <= h && yy <= w) {
				if (arr[xx][yy] == 1 && !visit[xx][yy])
					dfs(xx, yy);
			}
		}
		return 1;
	}

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		while (true) {

			int cnt = 0;
			w = scan.nextInt();
			h = scan.nextInt();

			if (w == 0 && h == 0)
				break;

			arr = new int[h + 1][w + 1];
			visit = new boolean[h + 1][w + 1];
			for (int i = 1; i <= h; i++) {
				for (int j = 1; j <= w; j++)
					arr[i][j] = scan.nextInt();
			}

			for (int i = 1; i <= h; i++) {
				for (int j = 1; j <= w; j++) {
					if (arr[i][j] == 1 && !visit[i][j])
						cnt += dfs(i, j);
				}
			}
			System.out.println(cnt);
		}
		scan.close();
	}
}