1
class Solution {
2
  public int dfs(int[][] grid, int i, int j) {
3
    if (i == grid.length) return j;
4

5
    if (j < 0 || j >= grid[0].length) return -1;
6

7
    if (grid[i][j] == 1 && j + 1 < grid[0].length && grid[i][j + 1] == 1)
8
      return dfs(grid, i + 1, j + 1);
9
    else if (grid[i][j] == -1 && j - 1 >= 0 && grid[i][j - 1] == -1) return dfs(grid, i + 1, j - 1);
10

11
    return -1;
12
  }
13

14
  public int[] findBall(int[][] grid) {
15
    int m = grid[0].length;
16
    int[] ar = new int[m];
17

18
    for (int j = 0; j < m; j++) ar[j] = dfs(grid, 0, j);
19

20
    return ar;
21
  }
22
}