A-LevelComputer ScienceAlgorithm design and problem-solving9618/23 · May/June 2021 · Q58 Marks

A global 2D array Result of type INTEGER is used to store a list of exam candidate numbers together with their marks. The array contains 2000 elements, organised as 1000 rows and 2 columns. Column 1 contains the candidate number and column 2 contains the mark for the corresponding candidate. All elements contain valid exam result data. A procedure Sort() is needed to sort Result into ascending order of mark using an efficient bubble sort algorithm. Write pseudocode for the procedure Sort().

A procedure Sort() is needed to sort Result into ascending order of mark using an efficient bubble sort algorithm. Write pseudocode for the procedure Sort().[8]

Mark scheme

Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.

[1] Outer loop
[1] Inner loop
[1] Correct comparison in a loop
[1] Correct swap of col1 array elements in a loop
[1] Correct swap of col2 array elements in a loop (via loop or separate statements)
[1] 'NoSwap' mechanism: Conditional outer loop including flag reset
[1] 'NoSwap' mechanism: Set flag in inner loop to indicate swap
[1] Reducing Boundary in the outer loop

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