Given a non-empty 2D matrix matrix and an integer k, find the max sum of a rectangle in the matrix such that its sum is no larger than k.
Given matrix = [ [1, 0, 1], [0, -2, 3] ] k = 2
The answer is
2. Because the sum of rectangle
[[0, 1], [-2, 3]] is 2 and 2 is the max number no larger than k (k = 2).
Special thanks to @fujiaozhu for adding this problem and creating all test cases.