Range of motion of leecode robot

There is one on the ground m That's ok n Grid of columns , From coordinates [0,0] To coordinates [m-1,n-1]. A robot from coordinates [0, 0] The grid starts to move , It can go left every time 、 Right 、 On 、 Move down one space （ Can't move out of the box ）, The sum of the digits of row coordinates and column coordinates is greater than k Lattice of . for example , When k by 18 when , Robots can enter the grid [35, 37] , because 3+5+3+7=18. But it can't get into the grid [35, 38], because 3+5+3+8=19. How many squares can the robot reach ？

Example 1：

 Input ：m = 2, n = 3, k = 1
 Output ：3

Example 2：

 Input ：m = 3, n = 1, k = 0
 Output ：1

Tips ：

1 <= n,m <= 100
0 <= k <= 20

Two ways of traversal DFS/BFS

// Depth-first search dfs
class Solution {
    
    int m,n;
    boolean [][]visited;
    public int movingCount(int m, int n, int k) {
    
        this.m=m;
        this.n=n;
        visited=new boolean[m][n];
        return dfs(0,0,k);
    }
    public int dfs(int i,int j,int k){
    
        if(i>=m||j>=n
                || visited[i][j]
                || sum(i,j)>k
        )return 0;
        visited[i][j]=true;

        return 1+dfs(i+1,j,k)+dfs(i,j+1,k);


    }

    public int sum(int i,int j){
    
        int sum = 0;
        while (i != 0) {
    
            sum += i % 10;
            i /= 10;
        }
        while (j != 0) {
    
            sum += j % 10;
            j /= 10;
        }
        return sum;
    }
}

BFS

// Breadth first search 
class Solution {
    
    public int movingCount(int m, int n, int k) {
    
        boolean[][] visited = new boolean[m][n];
        int[][] direct = {
    {
    1, 0}, {
    0, 1}};
        int res = 0;
        Queue<AbstractMap.SimpleEntry<Integer, Integer>> queue = new LinkedList<>();
        queue.add(new AbstractMap.SimpleEntry<>(0, 0));
        while (!queue.isEmpty()) {
    
            AbstractMap.SimpleEntry<Integer, Integer> cor = queue.poll();
            Integer x = cor.getKey();
            Integer y = cor.getValue();
            int sum = x / 10 + x % 10 + y / 10 + y % 10;
            if (x < 0 || y < 0 || x >= m || y >= n || visited[x][y] || sum > k) {
    
                continue;
            }
            visited[x][y] = true;
            res++;
            for (int i = 0; i < 2; i++) {
    
                queue.add(new AbstractMap.SimpleEntry<>(x + direct[i][0], y + direct[i][1]));
            }
        }
        return res;
    }
}