2025 OCR A-LEVEL COMPUTER SCIENCE H446/02 Algorithms and Programming Question Paper &
Mark Scheme (Merged) June 2025 [VERIFIED]
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[601/4911/5] DC Charity Turn over
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, 2
Section A
1 Data in a computer program needs to be sorted.
(a)
(i) Describe the steps a bubble sort will take to sort items into ascending order.
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(ii) Darcie and Felix have both written a program that will perform a bubble sort to put these
numbers into ascending order.
2 1 3 4 5 6 7
Darcie’s version will complete six passes. However, Felix’s version will only need to complete
two passes.
Explain how Felix may have made his version more efficient than Darcie’s version.
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(b) A second type of sorting algorithm is an insertion sort.
Describe how an insertion sort can be used to put the following data into ascending order.
20 8 15 36
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(c) A third type of sorting algorithm is a quick sort.
The following quick sort algorithm is made up of two functions called partition()and
quickSort(). The algorithm will sort an integer array into ascending numerical order.
01 function partition(array, low, high) 02
pivot = array[high]
03 index = low - 1
04 for count = low to high-1
05 if array[count] < pivot then 06
index = index + 1
07 temp = array[index]
08 array[index] = array[count]
09 array[count] = temp
10 endif
11 next count
12 temp = array[index + 1]
13 array[index + 1] = array[high]
14 array[high] = temp
15 return index + 1
16 endfunction
17
18 function quickSort(array, low, high)
19 if low < high then
20 partitionIndex = partition(array, low, high)
21 quickSort(array, low, partitionIndex - 1)
22 quickSort(array, partitionIndex + 1, high)
23 endif
24 endfunction
(i) Identify which of the two functions is recursive and give all of the line numbers where
recursive calls are made.
Recursive function name ..................................................................................................................
© OCR 2025
Mark Scheme (Merged) June 2025 [VERIFIED]
© OCR 2025 OCR is an exempt
[601/4911/5] DC Charity Turn over
(PQ/CGW)
337417/5
, 2
Section A
1 Data in a computer program needs to be sorted.
(a)
(i) Describe the steps a bubble sort will take to sort items into ascending order.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
. ....................................................................................................................................................... [5]
(ii) Darcie and Felix have both written a program that will perform a bubble sort to put these
numbers into ascending order.
2 1 3 4 5 6 7
Darcie’s version will complete six passes. However, Felix’s version will only need to complete
two passes.
Explain how Felix may have made his version more efficient than Darcie’s version.
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
. ....................................................................................................................................................... [2]
© OCR 2025
, 3
(b) A second type of sorting algorithm is an insertion sort.
Describe how an insertion sort can be used to put the following data into ascending order.
20 8 15 36
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..........................................................................................................................................................
..........................................................................................................................................................
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..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
..........................................................................................................................................................
. ....................................................................................................................................................... [5]
© OCR 2025 Turn over
, 4
(c) A third type of sorting algorithm is a quick sort.
The following quick sort algorithm is made up of two functions called partition()and
quickSort(). The algorithm will sort an integer array into ascending numerical order.
01 function partition(array, low, high) 02
pivot = array[high]
03 index = low - 1
04 for count = low to high-1
05 if array[count] < pivot then 06
index = index + 1
07 temp = array[index]
08 array[index] = array[count]
09 array[count] = temp
10 endif
11 next count
12 temp = array[index + 1]
13 array[index + 1] = array[high]
14 array[high] = temp
15 return index + 1
16 endfunction
17
18 function quickSort(array, low, high)
19 if low < high then
20 partitionIndex = partition(array, low, high)
21 quickSort(array, low, partitionIndex - 1)
22 quickSort(array, partitionIndex + 1, high)
23 endif
24 endfunction
(i) Identify which of the two functions is recursive and give all of the line numbers where
recursive calls are made.
Recursive function name ..................................................................................................................
© OCR 2025
