Computer Science · May / June 2025 · Paper 22 · Question 6
0478
As printed in the paper
The question as text
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Show the answer and mark scheme
6(a)[6]
One mark per mark point
MP1 Correct Number and Index columns
MP2 Correct Word column
MP3 Correct Continue column
MP4 Correct V1 and V2 column
MP5 Correct L1 and L2 column
MP6 Correct OUTPUT column
Number Index
Word
Continue V1 V2 L1 L2
OUTPUT 2
1
RACECAR
TRUE
1
7
R
R
2
6
A
A
3
5
C
C
4
4
Successful 2
TREAT
TRUE
1
5
T
T
2
4
R
A
FALSE
NOT successful
6(b)[1]
Finds words that read the same forwards and backwards.
6(c)[3]
One mark per mark point, max three
MP1 Uses an index to mark the start and end of each word // uses V1 to mark the start of the word and V2 to mark the end
MP2 After each check, these are moved to the next character in the word at each end of the word // V1 is incremented by 1 and V2 is decremented by 1 after each check.
MP3 When the two indexes match or cross, the whole word has been checked // When V1 = V2 or V1 > V2, the whole word has been checked
MP4 The algorithm will exit if it is found that two compared letters are not the same.
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