# 1219. Path with Maximum Gold

<https://leetcode.com/problems/path-with-maximum-gold>

## Description

In a gold mine `grid` of size `m x n`, each cell in this mine has an integer representing the amount of gold in that cell, `0` if it is empty.

Return the maximum amount of gold you can collect under the conditions:

* Every time you are located in a cell you will collect all the gold in that cell.
* From your position, you can walk one step to the left, right, up, or down.
* You can't visit the same cell more than once.
* Never visit a cell with `0` gold.
* You can start and stop collecting gold from **any** position in the grid that has some gold.

**Example 1:**

```
**Input:** grid = [[0,6,0],[5,8,7],[0,9,0]]
**Output:** 24
**Explanation:**
[[0,6,0],
 [5,8,7],
 [0,9,0]]
Path to get the maximum gold, 9 -> 8 -> 7.
```

**Example 2:**

```
**Input:** grid = [[1,0,7],[2,0,6],[3,4,5],[0,3,0],[9,0,20]]
**Output:** 28
**Explanation:**
[[1,0,7],
 [2,0,6],
 [3,4,5],
 [0,3,0],
 [9,0,20]]
Path to get the maximum gold, 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7.
```

**Constraints:**

* `m == grid.length`
* `n == grid[i].length`
* `1 <= m, n <= 15`
* `0 <= grid[i][j] <= 100`
* There are at most **25** cells containing gold.

## ac

```java
```