AQA Computer Science - Paper 1
PROGRAMMING 2024
Algorithm A methodical, logical rule or procedure that guarantees solving a
particular problem.
Difference between algorithms and computer programs Computer programs are
implementations of algorithms
Decomposition The process of breaking down larger problems into smaller
more manageable sub problems
Abstraction The removal of unnecessary information to make a problem easier to
understand
Steps to answer : Describe this algorithm in terms of inputs and outputs 1)
draw an input and output table that shows the inputs and outputs
2) State the inputs, what data structure they are, their datatype and its name
3) State the outputs, what data structure they are, their datatype, where its going
and its name
Steps to answer : why one algorithm is more efficient than another 1) Compare
how many calculations are taking place
2) Compare the number of complex structures (Iteration and Selection)
,AQA Computer Science - Paper 1
PROGRAMMING 2024
3) And therefore it would run in less time
DO NOT SAY THERE ARE FEWER LINES OF CODES CAUSE THAT IS WRONG AND
JUST STUPID
Flowcharts A graphical representation of the steps in a process; details all of the
elements in a process and the sequence in which these elements occur. A form of
algorithm
Oval Shows the start and end of a flowchart
Rectangle A process, i.e addition, division
Parallelogram An input or output
Diamond A decision
Arrows Shows the flow of information
Linear Search a method for finding a target value within a list. It sequentially
checks each element of the list for the target value until a match is found or until
all the elements have been searched. Works even if the list is unsorted.
linear search advantages Simple, Works on unsorted data
Linear search disadvantages Not efficient in very long lists
,AQA Computer Science - Paper 1
PROGRAMMING 2024
Binary Search Looking for an item in an already sorted list by eliminating
large portions of the data on each comparison. Continuously divides the list in 2
discarding the set which has numbers greater than the number being searched.
Binary search advantagesExtremely efficient
Binary search disadvantages Doesn't work on unsorted data
Bubble Sort A sort in which the first two items to be sorted are examined and
exchanged if necessary to place them in the specified order; the second item is
then compared with the third (exchanging them if required), the third is compared
with the fourth, and the process is repeated until all pairs have been examined
and all items are in the proper sequence.
Bubble sort advantages - it is a simple algorithm that can easily be implemented
on a computer
- it's an efficient way to check if a list is already in order
- doesn't use a lot of memory as all the sorting is done using the original list
Bubble sort disadvantages - it is an inefficient way to sort a list
, AQA Computer Science - Paper 1
PROGRAMMING 2024
- due to being inefficient, the bubble sort algorithm doesn't cope well with a very
large list
Merge Sort A 2 stage sort, 1st stage - the list is successively divided in half,
forming 2 sublists and is repeated until each sublist is of length one. 2nd stage -
each pair of lists are merged in order until there is one sorted string of numbers
remaining
Merge Sort Advantages Much more efficient process as it takes much less time
to execute
Merge sort disadvantages It is quite a difficult algorithm to implement and it
requires more memory to store all the sublists which is an issue for large lists
Data types Integer - A whole number - 2 or 4 bytes
Real / Float / Double - A decimal number - 4 or 8 bytes
Char - A single character - 1 byte
String - Many characters - 1 byte per character
Boolean - True / False - 1 byte
Arithmetic Operators + - addition
PROGRAMMING 2024
Algorithm A methodical, logical rule or procedure that guarantees solving a
particular problem.
Difference between algorithms and computer programs Computer programs are
implementations of algorithms
Decomposition The process of breaking down larger problems into smaller
more manageable sub problems
Abstraction The removal of unnecessary information to make a problem easier to
understand
Steps to answer : Describe this algorithm in terms of inputs and outputs 1)
draw an input and output table that shows the inputs and outputs
2) State the inputs, what data structure they are, their datatype and its name
3) State the outputs, what data structure they are, their datatype, where its going
and its name
Steps to answer : why one algorithm is more efficient than another 1) Compare
how many calculations are taking place
2) Compare the number of complex structures (Iteration and Selection)
,AQA Computer Science - Paper 1
PROGRAMMING 2024
3) And therefore it would run in less time
DO NOT SAY THERE ARE FEWER LINES OF CODES CAUSE THAT IS WRONG AND
JUST STUPID
Flowcharts A graphical representation of the steps in a process; details all of the
elements in a process and the sequence in which these elements occur. A form of
algorithm
Oval Shows the start and end of a flowchart
Rectangle A process, i.e addition, division
Parallelogram An input or output
Diamond A decision
Arrows Shows the flow of information
Linear Search a method for finding a target value within a list. It sequentially
checks each element of the list for the target value until a match is found or until
all the elements have been searched. Works even if the list is unsorted.
linear search advantages Simple, Works on unsorted data
Linear search disadvantages Not efficient in very long lists
,AQA Computer Science - Paper 1
PROGRAMMING 2024
Binary Search Looking for an item in an already sorted list by eliminating
large portions of the data on each comparison. Continuously divides the list in 2
discarding the set which has numbers greater than the number being searched.
Binary search advantagesExtremely efficient
Binary search disadvantages Doesn't work on unsorted data
Bubble Sort A sort in which the first two items to be sorted are examined and
exchanged if necessary to place them in the specified order; the second item is
then compared with the third (exchanging them if required), the third is compared
with the fourth, and the process is repeated until all pairs have been examined
and all items are in the proper sequence.
Bubble sort advantages - it is a simple algorithm that can easily be implemented
on a computer
- it's an efficient way to check if a list is already in order
- doesn't use a lot of memory as all the sorting is done using the original list
Bubble sort disadvantages - it is an inefficient way to sort a list
, AQA Computer Science - Paper 1
PROGRAMMING 2024
- due to being inefficient, the bubble sort algorithm doesn't cope well with a very
large list
Merge Sort A 2 stage sort, 1st stage - the list is successively divided in half,
forming 2 sublists and is repeated until each sublist is of length one. 2nd stage -
each pair of lists are merged in order until there is one sorted string of numbers
remaining
Merge Sort Advantages Much more efficient process as it takes much less time
to execute
Merge sort disadvantages It is quite a difficult algorithm to implement and it
requires more memory to store all the sublists which is an issue for large lists
Data types Integer - A whole number - 2 or 4 bytes
Real / Float / Double - A decimal number - 4 or 8 bytes
Char - A single character - 1 byte
String - Many characters - 1 byte per character
Boolean - True / False - 1 byte
Arithmetic Operators + - addition
