机器人的运动范围（dfs）（leetcode 4.8 每日打卡）

 1 int dfs(int m, int n, int k, int i, int j, int *visited)
 2 {
 3     if(i < 0 || i == m || j < 0 || j == n || visited[i*n + j] == 1 || i%10+i/10+j%10+j/10 > k)
 4     {
 5         return 0;
 6     }
 7     visited[i*n + j] = 1;
 8     return dfs(m,n,k,i+1,j,visited) + dfs(m,n,k,i,j+1,visited) + 1;
 9 }
10 
11 int movingCount(int m, int n, int k)
12 {
13     int visited[m * n];
14     memset(visited,0,m*n*sizeof(int));
15     int ans = dfs(m,n,k,0,0,(int *)visited);
16     return ans;
17 }