| Exam Board | Edexcel |
|---|---|
| Module | D1 (Decision Mathematics 1) |
| Year | 2005 |
| Session | June |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Sorting Algorithms |
| Type | Quick Sort Execution |
| Difficulty | Easy -1.8 This is a purely algorithmic question requiring mechanical application of the quick sort algorithm with no problem-solving or mathematical insight. Students simply follow the prescribed procedure step-by-step, making it significantly easier than average A-level maths questions which typically require some conceptual understanding or multi-step reasoning. |
| Spec | 7.03k Sorting: quick sort |
| Ali | 74 |
| Bobby | 28 |
| Eun-Jung | 63 |
| Katie | 54 |
| Marciana | 54 |
| Peter | 49 |
| Rory | 37 |
| Sophie | 68 |
| Answer | Marks | Guidance |
|---|---|---|
| Content | Marks | Guidance |
| Sorting: \(74, 28, 63, 54, 54, 49, 37, 68\) or similar valid arrangements | M1 | Pivot clear; list \(> 12\). Bubble not ok. M0 |
| First partition correct, next pivot correctly selected consistently | A1 | 1st pass correct, next pivot comectl selected consistently each time. Penalise fragmented list here |
| 2nd and 3rd passes correct, pivot for next pass selected consistently each time (or list rewritten in divisions as pivots) | A1∧ | c.s.o. + start statement (o.e.). Penalise non-sig. re-error here. Penalise "sloppers" here |
| A1 | c.a.o. accept c.a.even me |
| **Content** | **Marks** | **Guidance** |
|---|---|---|
| Sorting: $74, 28, 63, 54, 54, 49, 37, 68$ or similar valid arrangements | M1 | Pivot clear; list $> 12$. Bubble not ok. M0 |
| First partition correct, next pivot correctly selected consistently | A1 | 1st pass correct, next pivot comectl selected consistently each time. Penalise fragmented list here |
| 2nd and 3rd passes correct, pivot for next pass selected consistently each time (or list rewritten in divisions as pivots) | A1∧ | c.s.o. + start statement (o.e.). Penalise non-sig. re-error here. Penalise "sloppers" here |
| | A1 | c.a.o. accept c.a.even me |
---The table shows the marks obtained by students in a test. The students are listed in alphabetical order. Carry out a quick sort to produce a list of students in descending order of marks. You should show the result of each pass and identify your pivots clearly.
\begin{center}
\begin{tabular}{|c|c|}
\hline
Ali & 74 \\
\hline
Bobby & 28 \\
\hline
Eun-Jung & 63 \\
\hline
Katie & 54 \\
\hline
Marciana & 54 \\
\hline
Peter & 49 \\
\hline
Rory & 37 \\
\hline
Sophie & 68 \\
\hline
\end{tabular}
\end{center}
(Total 5 marks)
\hfill \mbox{\textit{Edexcel D1 2005 Q1}}