Question: We are given four items, namely A , B , C , and D . Their corresponding unit profits are pA , pB , pC

We are given four items, namely A, B, C, and D. Their corresponding unit profits are pA, pB , pC ,
and pD . The following shows five transactions with these items. Each row corresponds to a transaction where
a non-negative integer shown in the row corresponds to the total number of occurrences of the correspondence
item present in the transaction.
T A B C D
t10032
t23400
t30013
t41035
t56000
The frequency of an itemset in a row is defined to be the minimum of the number of occurrences of
all items in the itemset. For example, itemset {C, D} in the first row has frequency equals 2. But,
itemset {C, D} in the third row has frequency as 1.
The frequency of an itemset in the dataset is defined to be the sum of the frequencies of the itemset
in all rows in the dataset. For example, itemset {C, D} has frequency 2+0+1+3+0=6.
Let f be a function defined on an itemset s (f will be specified later). One example of this functions is
f (s)=
i in s pi. In this example, if s ={C, D}, then f (s)= pC + pD .
The profit of an itemset s in the dataset is defined to be the product of the frequency of this itemset
in the dataset and f (s). For example, itemset {C, D} has profit 6\times f ({C, D}).
Answer the following two questions based on the above problem setting.
(a) Assume f (s)=
i in s pi
|s|, where |s| is the size of s. Suppose that we know pA =10, pB =10, pC =10,
and pD =10. We want to find all itemsets with profit at least 50. Can the Apriori Algorithm be adapted
to find these itemsets? If yes, please write down the pseudo-code and illustrate it with the above example.
If no, please explain why. In this case, please also design an algorithm for this problem and write down the
pseudo-code.
(b) Assume f (s)=
i in s pi. Suppose that we know pA =5, pB =10, pC =6, and pD =4. We want to find
all itemsets with profit at least 50. Can the Apriori Algorithm be adapted to find these itemsets? If yes,
please write down the pseudo-code and illustrate it with the above example. If no, please explain why. In
this case, please also design an algorithm for this problem and write down the pseudo-code.

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