Maximum Sum Rectangle Problem Statement

Given a matrix ARR with dimensions N x M, your task is to identify the rectangle within the matrix that has the maximum sum of its elements.

Input:

The first line contains an integer T denoting the number of test cases. For each test case: 
The first line contains two space-separated integers N and M (the dimensions of the matrix).
The next N lines contain M space-separated integers representing the matrix ARR.

Output:

For each test case, output the maximum sum of the rectangles possible in the matrix on a new line.

Example:

Explanation:

The input matrix might be:
4 - 5 3 0 
-3 2 1 0 
1 -3 3 9

The maximum sum rectangle can be from (1,1) to (3,3), yielding a maximum sum of 29.

Constraints:

• 1 ≤ T ≤ 10
• 1 ≤ M, N ≤ 75
• -10^5 ≤ ARR[i][j] ≤ 10^5
• Time Limit: 1 sec

Note:

No need for any printing, focus on implementing the required function.