This pseudocode is an algorithm. DECLARE Word : STRING DECLARE V1 : INTEGER DECLARE V2 : INTEGER DECLARE Number : INTEGER DECLARE Index : INTEGER DECLARE L1 : CHAR DECLARE L2 : CHAR DECLARE Continue : BOOLEAN INPUT Number FOR Index ← 1 TO Number INPUT Word Continue ← TRUE V1 ← 1 V2 ← LENGTH(Word) WHILE Continue = TRUE AND V1 < V2 DO L1 ← SUBSTRING(Word, V1, 1) L2 ← SUBSTRING(Word, V2, 1) IF L1 <> L2 THEN Continue ← FALSE ELSE V1 ← V1 + 1 V2 ← V2 - 1 ENDIF ENDWHILE IF Continue = TRUE THEN OUTPUT "Successful" ELSE OUTPUT "NOT successful" ENDIF NEXT Index

Mark scheme

Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.

1. [6] (a) 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
2. (a) Trace Table (expected content, row by row where changes occur):
3. Number: 2
4. Index: 1
5. Word: RACECAR
6. Continue: TRUE
7. V1: 1
8. V2: 7
9. L1: R
10. L2: R
11. V1: 2
12. V2: 6
13. L1: A
14. L2: A
15. V1: 3
16. V2: 5
17. L1: C
18. L2: C
19. V1: 4
20. V2: 4
21. OUTPUT: Successful
22. Index: 2
23. Word: TREAT
24. Continue: TRUE
25. V1: 1
26. V2: 5
27. L1: T
28. L2: T
29. V1: 2
30. V2: 4
31. L1: R
32. L2: A
33. Continue: FALSE
34. OUTPUT: NOT successful
35. [1] (b) Finds words that read the same forwards and backwards.
36. [3] (c) 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.