题解 | #机器人的运动范围#

public class Solution {
    public int movingCount(int threshold, int rows, int cols) {
        int rst = 0;
        boolean[][] visits = new boolean[rows][cols];   
        LinkedList<Point> queue = new LinkedList<>();   //BFS
        queue.add(new Point(0,0));
        visits[0][0] = true;
        while(!queue.isEmpty()) {
            Point point = queue.poll();
            rst++;
            int[][] arr =  new int[][]{{1,0},{0,1}}; //向下向右扫过去
            for (int[] a : arr) {
                Point v = new Point(point.rows+a[0], point.cols+a[1]);
                boolean flag = isCanVisit(v, threshold, rows, cols);
                if(flag && !visits[v.rows][v.cols]) {
                    visits[v.rows][v.cols] = true;
                    queue.add(v);
                }
            }
        }
        return rst;
    }
    
    private boolean isCanVisit(Point point, int threshold, int rows, int cols) {
        if(point.rows < 0 || point.rows >= rows 
           || point.cols < 0 || point.cols >= cols || threshold <= 0) {
            return false;
        }
        int tmp = point.rows / 10 + point.rows % 10 + point.cols / 10 + point.cols % 10;
        return tmp <= threshold;
    }
}

class Point {
    int rows;
    int cols;
    public Point(int rows, int cols) {
        this.rows = rows;
        this.cols = cols;
    }
}