Trapping Rain Water in 2-D Elevation Map

You're given an M * N matrix where each value represents the height of that cell on a 2-D elevation map. Your task is to determine the total volume of water that can be trapped after it rains.

Example:

Input:

matrix = [[5, 5, 5],
[5, 2, 3],
[6, 9, 8]]

Output:

1

Explanation:

The elevation map allows 1 unit volume of water to be trapped, as illustrated in the image.

Constraints:

• 1 <= T <= 10
• 1 <= M, N <= 100
• 1 <= matrix[i][j] <= 10^3
• Where ‘T’ is the number of test cases, ‘M’ and ‘N’ are the dimensions of the given matrix.
• Matrix[i][j] is the height of the cell at the ‘i-th’ row and ‘j-th’ column.
• Time Limit: 1 sec.

Note:

You don't need to print anything, as it has already been taken care of. Just implement the given function.