edge cases in Java expect null instead of empty list, this is not according to spec, and is a knife in the back of users that use recursion to solve this problem ;)

Trying this in C++.
Seems that the algo you want is a bit 'oriented' => tried a solution that gives the sames results on many tests cases but... not the same amount of the 'same' rectangles (meaning, for example, (3*2) coming 2 times on your sol and 3 times in mine) for a few...