Matrix Cells in Distance Order

给一个点，按照曼哈顿距离排序所有矩阵上的点。讨论中直接sort的都是耍流氓-_-

class Solution {
     public int[][] allCellsDistOrder(int R, int C, int r0, int c0) {
        int[][] d = {{0, 1}, {1, 0},{0, -1}, {-1, 0}};
        int[][] res = new int[R*C][2];
        int count = 0;
        Queue<int[]> q = new LinkedList<int[]>();
        Set<String> check = new HashSet<String>();
        q.add(new int[]{r0, c0});
        check.add(r0+"|"+c0);
        while(!q.isEmpty()) {
            int[] t = q.poll();
            res[count++] = t;
            for(int i = 0 ; i < d.length; i++) {
                int newR = t[0]+d[i][0];
                int newC = t[1]+d[i][1];
                if(newR < R && newR>=0 && newC < C && newC>=0 && !check.contains(newR+"|"+newC)){
                    q.add(new int[]{newR, newC});
                    check.add(newR+"|"+newC);
                }
            }
        }
        return res;
    }
}