Divide and conquer challenge

Question

I send you this challenge, create a program which gets a matrix of integers which can be positive and negative and returns the maximum sum of a rectangular submatrix in O(N^3) complexity using divide and conquer paradigm

Answer 1

what should be the size of submatrix?

Answer 2

ok, so size of submatrix can be variable.

Answer 3

it should be N×M

Answer 4

Yes,that is right