[알고리즘] 백준 - 1926 (그림) / 자바

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class Main {

	static Queue<Node> queue;
    static int dx[] = {1, 0, -1, 0}; 
    static int dy[] = {0, 1, 0, -1};
	static int N;
	static int M;
	static int map[][];
	static boolean visited[][];
	static int drawCount = 0;
	static int maxDrawSize = 0;
	
	public static void main(String[] args) throws IOException {

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		N = Integer.parseInt(st.nextToken());
		M = Integer.parseInt(st.nextToken());
		map = new int[N][M];
		visited=  new boolean[N][M];
		for (int i = 0; i < N; i++) {
			st = new StringTokenizer(br.readLine());
			for (int j = 0; j < M; j++) {
				map[i][j] = Integer.parseInt(st.nextToken());
			}
		}

		for (int i = 0; i < N; i++) {
			for (int j = 0; j < M; j++) {
				if (map[i][j] == 1 && !visited[i][j]) {
					bfs(i, j);
				}
			}
		}
		;.
		System.out.println(drawCount);
		System.out.println(maxDrawSize);

	}

	public static void bfs(int x, int y) {
		queue = new LinkedList<>();
		queue.add(new Node(x, y));
		int count = 0 ;
		while (!queue.isEmpty()) {
			Node node = queue.poll();		
			count++;
			for (int dir = 0; dir < 4; dir++) {
                int nx = node.x + dx[dir];
                int ny = node.y + dy[dir];
                if (nx < 0 || nx >= N || ny < 0 || ny >= M) continue;
                if (visited[nx][ny] || map[nx][ny] == 0) continue;
                visited[nx][ny] = true;
                queue.add(new Node(nx, ny));
            }
		}
		
		drawCount++;
		if(count >1 ) {
			count--;
		}
		maxDrawSize = Math.max(maxDrawSize, count);


		
	}
}

class Node {
	int x;
	int y;


	public Node(int x, int y) {
		super();
		this.x = x;
		this.y = y;

	}

}