1594. Maximum Non Negative Product in a Matrix

public class Solution
{
    public int MaxProductPath(int[][] grid)
    {
        const int MOD = 1_000_000_007;
        int m = grid.Length;
        int n = grid[0].Length;
        // dpMin[i][j] := the minimum product from (0, 0) to (i, j)
        // dpMax[i][j] := the maximum product from (0, 0) to (i, j)
        long[,] dpMin = new long[m, n];
        long[,] dpMax = new long[m, n];

        dpMin[0, 0] = dpMax[0, 0] = grid[0][0];

        for (int i = 1; i < m; ++i)
            dpMin[i, 0] = dpMax[i, 0] = dpMin[i - 1, 0] * grid[i][0];

        for (int j = 1; j < n; ++j)
            dpMin[0, j] = dpMax[0, j] = dpMin[0, j - 1] * grid[0][j];

        for (int i = 1; i < m; ++i)
        {
            for (int j = 1; j < n; ++j)
            {
                if (grid[i][j] < 0)
                {
                    dpMin[i, j] = Math.Max(dpMax[i - 1, j], dpMax[i, j - 1]) * grid[i][j];
                    dpMax[i, j] = Math.Min(dpMin[i - 1, j], dpMin[i, j - 1]) * grid[i][j];
                }
                else
                {
                    dpMin[i, j] = Math.Min(dpMin[i - 1, j], dpMin[i, j - 1]) * grid[i][j];
                    dpMax[i, j] = Math.Max(dpMax[i - 1, j], dpMax[i, j - 1]) * grid[i][j];
                }
            }
        }

        long mx = Math.Max(dpMin[m - 1, n - 1], dpMax[m - 1, n - 1]);
        return mx < 0 ? -1 : (int)(mx % MOD);
    }
}