# 0505. The Maze II

https://leetcode.com/problems/the-maze-ii

## Description

There is a ball in a `maze` with empty spaces (represented as `0`) and walls (represented as `1`). The ball can go through the empty spaces by rolling **up, down, left or right**, but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction.

Given the `m x n` `maze`, the ball's `start` position and the `destination`, where `start = [startrow, startcol]` and `destination = [destinationrow, destinationcol]`, return _the shortest **distance** for the ball to stop at the destination_. If the ball cannot stop at `destination`, return `-1`.

The **distance** is the number of **empty spaces** traveled by the ball from the start position (excluded) to the destination (included).

You may assume that **the borders of the maze are all walls** (see examples).

**Example 1:**

![](https://assets.leetcode.com/uploads/2021/03/31/maze1-1-grid.jpg)

```
**Input:** maze = [[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]], start = [0,4], destination = [4,4]
**Output:** 12
**Explanation:** One possible way is : left -> down -> left -> down -> right -> down -> right.
The length of the path is 1 + 1 + 3 + 1 + 2 + 2 + 2 = 12.
```

**Example 2:**

![](https://assets.leetcode.com/uploads/2021/03/31/maze1-2-grid.jpg)

```
**Input:** maze = [[0,0,1,0,0],[0,0,0,0,0],[0,0,0,1,0],[1,1,0,1,1],[0,0,0,0,0]], start = [0,4], destination = [3,2]
**Output:** -1
**Explanation:** There is no way for the ball to stop at the destination. Notice that you can pass through the destination but you cannot stop there.
```

**Example 3:**

```
**Input:** maze = [[0,0,0,0,0],[1,1,0,0,1],[0,0,0,0,0],[0,1,0,0,1],[0,1,0,0,0]], start = [4,3], destination = [0,1]
**Output:** -1
```

**Constraints:**

* `m == maze.length`
* `n == maze[i].length`
* `1 <= m, n <= 100`
* `maze[i][j]` is `0` or `1`.
* `start.length == 2`
* `destination.length == 2`
* `0 <= startrow, destinationrow <= m`
* `0 <= startcol, destinationcol <= n`
* Both the ball and the destination exist in an empty space, and they will not be in the same position initially.
* The maze contains **at least 2 empty spaces**.

## ac

```java
```
