-- Nov 28 In-Class Exercise
from the figure, for n= 12, take approximation with even split of n=8 and n=16,
per-node retrieval depth k = ( 10 + 15) / 2 = 12.5, round up to 13
from the figure, for n= 12, take approximation with even split of n=8 and n=16,
per-node retrieval depth k = ( 10 + 15) / 2 = 12.5, round up to 13