994. Rotting Oranges

class Solution {
    public int orangesRotting(int[][] grid) {
        if (grid == null || grid.length == 0 || grid[0].length == 0) {
            return 0;
        }
        int freshCount = 0;
        Queue<int[]> queue = new LinkedList<>();
        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[0].length; j++) {
                if (grid[i][j] == 2) {
                    queue.offer(new int[]{i, j});
                } else if (grid[i][j] == 1) {
                    freshCount++;
                }
            }
        }
        if (freshCount == 0) {
            return 0;
        }
        int count = 0;
        int[][] dirs = {`{1,0},{-1,0},{0,1},{0,-1}`};
        while (!queue.isEmpty()) {
            count ++;
            int size = queue.size();
            for (int i = 0; i < size; i++) {
                int[] point = queue.poll();
                for (int[] dir : dirs) {
                    int x = point[0] + dir[0];
                    int y = point[1] + dir[1];
                    if (x < 0 || y < 0 || x >= grid.length || y >= grid[0].length || grid[x][y] == 0 || grid[x][y] == 2) {
                        continue;
                    }
                    grid[x][y] = 2;
                    queue.offer(new int[]{x, y});
                    freshCount --;
                }
            }
        }
        return freshCount == 0 ? count - 1 : -1;
    }
}