A-level
COMPUTER SCIENCE
Paper 1
Monday 10 June 2024 Afternoon Time allowed: 2 hours 30 minutes
, 2
Section A
You are advised to spend no longer than 40 minutes on this section.
Enter your answers for Section A in your Electronic Answer Document.
You must save this document at regular intervals.
0 1 State three advantages of using subroutines.
For each advantage, you must explain how the advantage is achieved.
[3 marks]
0 2 Circular queues and linear queues are examples of data structures that can be
implemented using a fixed-length array.
0 2 . 1 Explain why, when implemented using a fixed-length array, a circular queue is usually
considered to be a better choice of data structure than a linear queue.
[2 marks]
0 2 . 2 Describe the steps that must be completed to remove (dequeue) an item from a
circular queue that has been implemented using a fixed-length array.
[5 marks]
0 3
0 3 . 1 Describe the Halting problem.
[2 marks]
0 3 . 2 Explain the importance of the Halting problem.
[1 mark]
, 3
0 4 Figure 1 shows four sets R, S, T and U. Three dots (…) means the remaining
members of the set follow the same pattern as the previous members of the set.
Figure 1
R = {a, b}
S = {a, abb, abbbb, abbbbbb, …}
T = {bb, bbbb, bbbbbb, …}
U = {c, d, bb, b}
0 4 . 1 What is meant by the cardinality of a set?
[1 mark]
0 4 . 2 Explain what is wrong with the statement:
‘The only subsets of R are the sets {a}, {b} and {a, b}’.
[1 mark]
0 4 . 3 How many members are there in the set formed by the intersection of R and U?
[1 mark]
0 4 . 4 The language defined by a regular expression can be represented as a set.
Explain the functionality of the | (vertical bar) metacharacter when it is used in a
regular expression.
[1 mark]
The members of the set V are strings that match the regular expression a?b+
Set W is formed by the union of sets S and T.
Set X is formed by the set operation V – W.
0 4 . 5 Write a regular expression that would match with all the members of the set W.
[2 marks]
0 4 . 6 Write a regular expression that would match with all the members of the set X.
[2 marks]
Turn over ►
, 4
0 5 (3 + 4) * 5 is an example of an infix expression. The same expression has
been represented in a different expression format in Figure 2.
Figure 2
3 4 + 5 *
0 5 . 1 What is the name of the expression format used in Figure 2?
[1 mark]
0 5 . 2 Represent the infix expression 5 + 2 * 3 + 4 in the same expression format
used in Figure 2.
[2 marks]
COMPUTER SCIENCE
Paper 1
Monday 10 June 2024 Afternoon Time allowed: 2 hours 30 minutes
, 2
Section A
You are advised to spend no longer than 40 minutes on this section.
Enter your answers for Section A in your Electronic Answer Document.
You must save this document at regular intervals.
0 1 State three advantages of using subroutines.
For each advantage, you must explain how the advantage is achieved.
[3 marks]
0 2 Circular queues and linear queues are examples of data structures that can be
implemented using a fixed-length array.
0 2 . 1 Explain why, when implemented using a fixed-length array, a circular queue is usually
considered to be a better choice of data structure than a linear queue.
[2 marks]
0 2 . 2 Describe the steps that must be completed to remove (dequeue) an item from a
circular queue that has been implemented using a fixed-length array.
[5 marks]
0 3
0 3 . 1 Describe the Halting problem.
[2 marks]
0 3 . 2 Explain the importance of the Halting problem.
[1 mark]
, 3
0 4 Figure 1 shows four sets R, S, T and U. Three dots (…) means the remaining
members of the set follow the same pattern as the previous members of the set.
Figure 1
R = {a, b}
S = {a, abb, abbbb, abbbbbb, …}
T = {bb, bbbb, bbbbbb, …}
U = {c, d, bb, b}
0 4 . 1 What is meant by the cardinality of a set?
[1 mark]
0 4 . 2 Explain what is wrong with the statement:
‘The only subsets of R are the sets {a}, {b} and {a, b}’.
[1 mark]
0 4 . 3 How many members are there in the set formed by the intersection of R and U?
[1 mark]
0 4 . 4 The language defined by a regular expression can be represented as a set.
Explain the functionality of the | (vertical bar) metacharacter when it is used in a
regular expression.
[1 mark]
The members of the set V are strings that match the regular expression a?b+
Set W is formed by the union of sets S and T.
Set X is formed by the set operation V – W.
0 4 . 5 Write a regular expression that would match with all the members of the set W.
[2 marks]
0 4 . 6 Write a regular expression that would match with all the members of the set X.
[2 marks]
Turn over ►
, 4
0 5 (3 + 4) * 5 is an example of an infix expression. The same expression has
been represented in a different expression format in Figure 2.
Figure 2
3 4 + 5 *
0 5 . 1 What is the name of the expression format used in Figure 2?
[1 mark]
0 5 . 2 Represent the infix expression 5 + 2 * 3 + 4 in the same expression format
used in Figure 2.
[2 marks]
