I don’t get the task of rubik’s cube puzzle. Can somebody please describe in more details what needs to be done, or what it is meant by saying visible cubes?
A Rubik’s cube is made of NxNxN smaller cubes, but some of these are not visible because they are “inside” the cube. Your task is to count the subcubes which are visible, because they are on one of the faces.
Putting this puzzle under ‘medium’ is a but exaggeration. Simple math, single line of answer code, no algorithm needed just a closed formula. Many easy puzzles are harder, but of course it is subjective what is harder what is easier.