230418 카카오프렌즈 컬러링북

static class Point {
    private int x;
    private int y;

    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }
}
private static final int[] DX = { -1, 0, 1, 0 };
private static final int[] DY = { 0, 1, 0, -1 };

private static boolean[][] visited;

public static int[] solution(int m, int n, int[][] picture) {
    int numberOfArea = 0;
    int maxSizeOfOneArea = 0;
    visited = new boolean[m][n];

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (picture[i][j] != 0 && !visited[i][j]) {
                int size = bfs(m, n, i, j, picture);
                maxSizeOfOneArea = Math.max(maxSizeOfOneArea, size);
                numberOfArea++;
            }
        }
    }

    return new int[] { numberOfArea, maxSizeOfOneArea };
}

private static int bfs(int m, int n, int x, int y, int[][] picture) {
    int size = 1;
    int target = picture[x][y];
    Queue<Point> queue = new LinkedList<>();

    visited[x][y] = true;
    queue.offer(new Point(x, y));

    while (!queue.isEmpty()) {
        Point p = queue.poll();

        for (int i = 0; i < 4; i++) {
            int nx = p.getX() + DX[i];
            int ny = p.getY() + DY[i];

            if (onPicture(m, n, nx, ny) && picture[nx][ny] == target && !visited[nx][ny]) {
                queue.offer(new Point(nx, ny));
                visited[nx][ny] = true;
                size++;
            }
        }
    }

    return size;
}

private static boolean onPicture(int m, int n, int nx, int ny) {
    return nx >= 0 && nx < m && ny >= 0 && ny < n;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/1829