[백준:2583] 영역구하기 - JAVA

import java.util.*;

public class Main{ 
    // 영역 구하기
 
    static int[] dx = {0,1,0,-1};
    static int[] dy = {1,0,-1,0};
    static int m;
    static int n;
    static int k;
    static boolean[][] visited;
    static int[][] map;
 
    private static void solution () {
        Scanner sc = new Scanner(System.in);
        m = sc.nextInt();
        n = sc.nextInt();
        k = sc.nextInt();
        map = new int[m][n];
        visited = new boolean[m][n];
        int count = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();
 
        for(int i=0; i<k; i++) {
            int lx = sc.nextInt(); // 왼쪽 위 x
            int ly = sc.nextInt(); // 왼쪽 위 y
            int rx = sc.nextInt(); // 오른쪽 아래 x
            int ry = sc.nextInt(); // 오른쪽 아래 y
            //그림을 거꾸로 하기 때문에
            
            for(int y=ly; y<ry; y++) {
                for(int x=lx; x<rx; x++) {
                    map[y][x] = 1;
                    //직사각형그려진 부분은 1
                }
            }
        }
        for(int i=0; i<m; i++) {
            for(int j=0; j<n; j++) {
                if(!visited[i][j] && map[i][j] == 0) {
                    int data = bfs(i, j);
                    list.add(data);
                    count++;
                }
            }
        }
 
        System.out.println(count);
        Collections.sort(list);
        for(int i=0; i<list.size(); i++) {
            System.out.print(list.get(i)+" ");
        }
    }
 
    private static int bfs(int x, int y) {
        Queue<int[]> queue = new LinkedList<int[]>();
        //큐에 좌표 저장
        queue.offer(new int[] {x, y});
        visited[x][y] = true;
        int cnt = 1;
 
        while (!queue.isEmpty()) {
            int[] data = queue.poll();
            int curX = data[0];
            int curY = data[1];
 
            for(int i=0; i<4; i++) {
                int nextX = curX + dx[i];
                int nextY = curY + dy[i];
 
                if(nextX >=0 && nextY >=0 && nextX < m && nextY < n) {
                    if(!visited[nextX][nextY] && map[nextX][nextY] == 0) {
                        visited[nextX][nextY] = true;
                        queue.offer(new int[]{nextX, nextY});
                        cnt++;
                    }
                }
            }
        }
        return cnt;
    }
 
    public static void main(String[] args) {
        solution();
    }

}