Answer from cs61c-cf (Aspandiar Dahmubed 16812056) for Question 2
Spatial locality! In the first example, it will be accessing different colummns per iteration which does not take advantage of spatial locality. However, in the second example, we would be accessing different rows per iteration and since items in a row are next to each other and would be loaded a few at at time into a cache, this would allow the use of spatial locality and hence allow for faster use of the code.