CT Week 6 Graded Assignments IIT Madras

1. In the “Scores” table, let S be the list of sequence numbers of rows which have marks greater than 75 in at least one subject. What does the variable count represent at the end of the execution of the pseudocode given below?

   
   

count = 0

while(Table 1 has more rows){

    Read the first row X in Table 1

    foreach c in S{

        if (X.SeqNo == c){

            if(X.Mathematics < 75 and X.Physics < 75){

                count = count + 1

            }

        }

    }

    Move X to Table 2

}

2. The following pseudocode is executed using the “Words” dataset. Assume that the rows in Table 1 are sorted in the increasing order of sequence number. What does the list L contain at the end of execution?

L = []

A = "None"

Read the first row X in Table 1

A = X.PartOfSpeech

Move X to Table 2

while(Table 1 has more rows){

    Read the first row X in Table 1

    if(X.PartOfSpeech == "Noun"){

        if(A == "Adjective"){

            L = L ++ [X.Word]

        }

    }

    A = X.PartOfSpeech

    Move X to Table 2

}

3.We have a non-empty list called authList that stores the names of all authors in the “Library” table sorted in alphabetical order of author names. There is one element corresponding to each book in the table. This results in many duplicates. The following procedure attempts to extract the unique list of authors, while preserving the sorted order. The pseudocode may have mistakes. Identify all such mistakes (if any). It is a Multiple Select Question (MSQ).

uniqueList = [], prev = "None"

uniqueList = uniqueList ++ first(authList)

prev = first(authList)

foreach x in rest(authList){

    if(x == prev){

        uniqueList = uniqueList ++ [x]

    }

    prev = x

}

4. The procedure visitedShop returns the list of names of people who have visited a particular shop in the “Shopping Bills” dataset. It accepts the shop’s name as a parameter. Additionally, each customer must be represented exactly once in the returned list. The following pseudocode may have mistakes. Identify all such mistakes(if any). It is a Multiple Select Question (MSQ).

Procedure visitedShop(shop)

    S = "None"

    while(Pile 1 has more cards){

        Read the top card X from Pile 1

        if(X.ShopName == shop){

            if(not(member(S, X.CustomerName))){

                S = S ++ [X.ShopName]

            }

        }

        Move X to Pile 2

    }

    return(S)

End visitedShop

Procedure member(L, name)

    present = True

    foreach x in L{

        if(x == name){

            present = True

            exitloop

        }

    }

    return(present)

End member

5. There may be multiple pairs having the same minimum distance. If we wish to find a pair of stations closest to the first station in the list, which of the following is the correct code fragment?

6. There may be multiple pairs having the same minimum distance. If we wish to find a pair of stations closest to the last station in the list, which of the following is the correct code fragment?

7. stns is a list that contains information about the sequence of stations visited by a train. Specifically, each element in this list is itself a list: [Arrival, Departure]. The first element in stns corresponds to the starting station for the train and the last element corresponds to the ending station for the train.

waitTime(arr, dep) is a procedure that accepts the arrival time and departure time of a train at a given station as input and returns the waiting time at that station in minutes.

We wish to find the average waiting time across all intermediate stations where the train stops and store this result in variable avg. The pseudocode may have mistakes. Identify all such mistakes (if any). It is a Multiple Select Question (MSQ).

total = 0, count = 0, avg = 0

foreach x in init(rest(stns)){

    total = total + waitTime(first(x), last(x))

    count = count + 1

}

if(count != 0){

    avg = total / count

}

8. Which of the following statements about the variable flag1 is True at the end of execution of the above pseudocode?

9. What does the variable count represent at the end of execution of the above pseudocode?

10. At the end of execution of the code given above, what can be said about the values stored by the Boolean variables flag1 and flag2?