Edexcel A-Level Computer Science 2024
Paper 1 and 2 Exam Questions and
Answers
Algorithm - Answer>>A sequence of instructions that perform a
specific task when followed. Algorithms are abstract and
independent of any system.
Algorithms should be - Answer>>precise, well-defined and finite
A computer programme - Answer>>is an implementation of an
algorithm
Pseudocode - Answer>>An informal description intended for
human reading, but resembles code. It has no standardised
syntax, but you need to be consistent.
Flow chart - Answer>>A graphic organizer that shows the steps
within a program. It contains start and end (bubble), process (box)
and decisions (diamond) blocks.
Linear search - Answer>>Checks each element to see if it
matches the target. It repeats until a match is found or the whole
list has been checked. Using a tracker variable which is a
boolean.
Binary search - Answer>>Continually divides a list by two,
eliminating the part of the list that cannot have you item in it. The
list must be fully ordered first to eliminate with any certainty.
Binary search works by simplification.
Worst time - Answer>>the number of comparisons a search has
to make
,Bubble sort - Answer>>In passes, going from the first to the last
element, the largest value 'bubbles' towards the end of the list
using pair comparisons and swapping.
Merge sort - Answer>>Divide: splits the inputted list into two
lists of similar size.
Conquer: sorts both sublists recursively, by repeating the
algorithm.
Combine: merge both sorted sublists into one sorted list.
Choosing an algorithm - Answer>>Certain algorithms only work
with certain types of data, and data that is structured in a specific
way, such as an array or graph. For searching, if the data is not
sorted then linear search must be used. Some algorithms need
large numbers to be efficient, such as radixsort.
Decomposition - Answer>>Breaking a problem down into
subproblems. Each subproblem should be of a similar level of
detail and accomplish an identifiable task. The problem needs to
be divided so that the sub-problems can be solved independently
of each other. Solutions to each sub-problem need to be
combined.
Abstraction - Answer>>Removing unnecessary detail from a
problem to simplify it, such as the tube map. An entity is abstract
only relative to the layer below. When designing an algorithm you
can ignore implementation details
Model (abstraction) - Answer>>A generalised view of a
problem. It is an abstraction.
Algorithmic thinking - Answer>>Problem-solving abilities related
to algorithms. You analyse requirements of a solution,
,communicate and specify a problem, designing algorithms and
considering special cases and efficiency.
Data types - Answer>>A means of classifying different data.
Data type determines - Answer>>The data's properties, such as
what operations can be done on the data and how the data will be
stored.
Integer - Answer>>Any whole number
Real/Float - Answer>>Numbers with a decimal part
Boolean - Answer>>One of two values, True or False
Character - Answer>>A letter, number of symbol
String - Answer>>A sequence of characters
Casting - Answer>>Changing the data type of a value
Sequence - Answer>>All lines are executed individually, line by
line
Selection - Answer>>Decisions made that determine the
execution, if statements.
Iteration - Answer>>The code is repeated until specified
conditions are met, while loops.
Count control loops/ Definite loops - Answer>>There are an
exact number of iterations known, such as for loops.
, Condition controlled loops/ Indefinite loops - Answer>>Iterates
dependent on a condition, such as while loops.
Variables - Answer>>Locations in the memory containing single
values. The memory location is paired with an identifier, the
variable name. The name, type and memory location usually
remain fixed but the values contained can change during the
programme's execution.
Initialisation - Answer>>The assignment of the first value of a
variable.
Constants - Answer>>Identifiers associated with values that
remain fixed during the programme's execution.
Why use constants? - Answer>>Readability: not everyone
maintaining the code will know the relevance and understand
what the values mean, a named constant makes it clear.
Ability to update: if you need to update the constant value, all you
need to do is update the initial value once.
Compiler optimisation: depending on the computer, use of named
constants can lead to optimisation, either improving performance
or reducing memory space.
Subprograms/ Subroutines/ Functions - Answer>>An 'out of
line' block of code that performs a specific task. They get used
and reused throughout the programme by 'calling' their name in a
statement, causing them to be executed.
Parameter/ Arguments - Answer>>Variable names/ Values
used for the input of a subprogram, used to 'pass in' data to a
subprogram.
Paper 1 and 2 Exam Questions and
Answers
Algorithm - Answer>>A sequence of instructions that perform a
specific task when followed. Algorithms are abstract and
independent of any system.
Algorithms should be - Answer>>precise, well-defined and finite
A computer programme - Answer>>is an implementation of an
algorithm
Pseudocode - Answer>>An informal description intended for
human reading, but resembles code. It has no standardised
syntax, but you need to be consistent.
Flow chart - Answer>>A graphic organizer that shows the steps
within a program. It contains start and end (bubble), process (box)
and decisions (diamond) blocks.
Linear search - Answer>>Checks each element to see if it
matches the target. It repeats until a match is found or the whole
list has been checked. Using a tracker variable which is a
boolean.
Binary search - Answer>>Continually divides a list by two,
eliminating the part of the list that cannot have you item in it. The
list must be fully ordered first to eliminate with any certainty.
Binary search works by simplification.
Worst time - Answer>>the number of comparisons a search has
to make
,Bubble sort - Answer>>In passes, going from the first to the last
element, the largest value 'bubbles' towards the end of the list
using pair comparisons and swapping.
Merge sort - Answer>>Divide: splits the inputted list into two
lists of similar size.
Conquer: sorts both sublists recursively, by repeating the
algorithm.
Combine: merge both sorted sublists into one sorted list.
Choosing an algorithm - Answer>>Certain algorithms only work
with certain types of data, and data that is structured in a specific
way, such as an array or graph. For searching, if the data is not
sorted then linear search must be used. Some algorithms need
large numbers to be efficient, such as radixsort.
Decomposition - Answer>>Breaking a problem down into
subproblems. Each subproblem should be of a similar level of
detail and accomplish an identifiable task. The problem needs to
be divided so that the sub-problems can be solved independently
of each other. Solutions to each sub-problem need to be
combined.
Abstraction - Answer>>Removing unnecessary detail from a
problem to simplify it, such as the tube map. An entity is abstract
only relative to the layer below. When designing an algorithm you
can ignore implementation details
Model (abstraction) - Answer>>A generalised view of a
problem. It is an abstraction.
Algorithmic thinking - Answer>>Problem-solving abilities related
to algorithms. You analyse requirements of a solution,
,communicate and specify a problem, designing algorithms and
considering special cases and efficiency.
Data types - Answer>>A means of classifying different data.
Data type determines - Answer>>The data's properties, such as
what operations can be done on the data and how the data will be
stored.
Integer - Answer>>Any whole number
Real/Float - Answer>>Numbers with a decimal part
Boolean - Answer>>One of two values, True or False
Character - Answer>>A letter, number of symbol
String - Answer>>A sequence of characters
Casting - Answer>>Changing the data type of a value
Sequence - Answer>>All lines are executed individually, line by
line
Selection - Answer>>Decisions made that determine the
execution, if statements.
Iteration - Answer>>The code is repeated until specified
conditions are met, while loops.
Count control loops/ Definite loops - Answer>>There are an
exact number of iterations known, such as for loops.
, Condition controlled loops/ Indefinite loops - Answer>>Iterates
dependent on a condition, such as while loops.
Variables - Answer>>Locations in the memory containing single
values. The memory location is paired with an identifier, the
variable name. The name, type and memory location usually
remain fixed but the values contained can change during the
programme's execution.
Initialisation - Answer>>The assignment of the first value of a
variable.
Constants - Answer>>Identifiers associated with values that
remain fixed during the programme's execution.
Why use constants? - Answer>>Readability: not everyone
maintaining the code will know the relevance and understand
what the values mean, a named constant makes it clear.
Ability to update: if you need to update the constant value, all you
need to do is update the initial value once.
Compiler optimisation: depending on the computer, use of named
constants can lead to optimisation, either improving performance
or reducing memory space.
Subprograms/ Subroutines/ Functions - Answer>>An 'out of
line' block of code that performs a specific task. They get used
and reused throughout the programme by 'calling' their name in a
statement, causing them to be executed.
Parameter/ Arguments - Answer>>Variable names/ Values
used for the input of a subprogram, used to 'pass in' data to a
subprogram.
