We have a two$-$word query. For one term the postings

list consists of the following $16$ entries:

$4,6,10,12,14,16,18,20,22,32,47,81,120,122,157,180$

and for the other it is the one entry postings list:

$[47].$

Work out how many comparisons would be done to

intersect the two postings lists with the following two

strategies. Briefly justify your answers $($Let $($x$,$y$)$ denote a

posting comparison. $x$ refers to a value in the upper list and

$y$ refers to a value in the lower list$)$

write down those comparisons$)$:

a$.$ Using standard postings lists

b$.$ Using postings lists stored with skip pointers, with a skip

length of $\sqrt[\phantom{2}]{P}($for a postings list of length $P).$