Maximum Non Negative Product in a Matrix
<p>You are given a <code>m x n</code> matrix <code>grid</code>. Initially, you are located at the top-left corner <code>(0, 0)</code>, and in each step, you can only <strong>move right or down</strong> in the matrix.</p>

<p>Among all possible paths starting from the top-left corner <code>(0, 0)</code> and ending in the bottom-right corner <code>(m - 1, n - 1)</code>, find the path with the <strong>maximum non-negative product</strong>. The product of a path is the product of all integers in the grid cells visited along the path.</p>

<p>Return the <em>maximum non-negative product <strong>modulo</strong> </em><code>10<sup>9</sup> + 7</code>. <em>If the maximum product is <strong>negative</strong>, return </em><code>-1</code>.</p>

<p>Notice that the modulo is performed after getting the maximum product.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1500-1599/1594.Maximum%20Non%20Negative%20Product%20in%20a%20Matrix/images/product1.jpg" style="width: 244px; height: 245px;" />
<pre>
<strong>Input:</strong> grid = [[-1,-2,-3],[-2,-3,-3],[-3,-3,-2]]
<strong>Output:</strong> -1
<strong>Explanation:</strong> It is not possible to get non-negative product in the path from (0, 0) to (2, 2), so return -1.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1500-1599/1594.Maximum%20Non%20Negative%20Product%20in%20a%20Matrix/images/product2.jpg" style="width: 244px; height: 245px;" />
<pre>
<strong>Input:</strong> grid = [[1,-2,1],[1,-2,1],[3,-4,1]]
<strong>Output:</strong> 8
<strong>Explanation:</strong> Maximum non-negative product is shown (1 * 1 * -2 * -4 * 1 = 8).
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1500-1599/1594.Maximum%20Non%20Negative%20Product%20in%20a%20Matrix/images/product3.jpg" style="width: 164px; height: 165px;" />
<pre>
<strong>Input:</strong> grid = [[1,3],[0,-4]]
<strong>Output:</strong> 0
<strong>Explanation:</strong> Maximum non-negative product is shown (1 * 0 * -4 = 0).
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 15</code></li>
	<li><code>-4 &lt;= grid[i][j] &lt;= 4</code></li>
</ul>
Array; Dynamic Programming; Matrix
class Solution:
    def maxProductPath(self, grid: List[List[int]]) -> int:
        m, n = len(grid), len(grid[0])
        mod = 10**9 + 7
        dp = [[[grid[0][0]] * 2 for _ in range(n)] for _ in range(m)]
        for i in range(1, m):
            dp[i][0] = [dp[i - 1][0][0] * grid[i][0]] * 2
        for j in range(1, n):
            dp[0][j] = [dp[0][j - 1][0] * grid[0][j]] * 2
        for i in range(1, m):
            for j in range(1, n):
                v = grid[i][j]
                if v >= 0:
                    dp[i][j][0] = min(dp[i - 1][j][0], dp[i][j - 1][0]) * v
                    dp[i][j][1] = max(dp[i - 1][j][1], dp[i][j - 1][1]) * v
                else:
                    dp[i][j][0] = max(dp[i - 1][j][1], dp[i][j - 1][1]) * v
                    dp[i][j][1] = min(dp[i - 1][j][0], dp[i][j - 1][0]) * v
        ans = dp[-1][-1][1]
        return -1 if ans < 0 else ans % mod
