2023 AQA A-level COMPUTER SCIENCE 7517/1 Paper 1 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED] A-level COMPUTER SCIENCE

2023 AQA A-level COMPUTER SCIENCE 7517/1 Paper 1 Question Paper & Mark scheme (Merged) June 2023 [VERIFIED] A-level COMPUTER SCIENCE Paper 1 Monday 12 June 2023 Afternoon Time allowed: 2 hours 30 minutes Materials For this paper you must have: • a computer • a printer • appropriate software • the Electronic Answer Document • an electronic version and a hard copy of the Skeleton Program • an electronic version and a hard copy of the Preliminary Material. You must not use a calculator. Instructions • Type the information required on the front of your Electronic Answer Document. • Before the start of the examination make sure your Centre Number, Candidate Name and Candidate Number are shown clearly in the footer of every page (also at the top of the front cover) of your Electronic Answer Document. • Enter your answers into the Electronic Answer Document. • Answer all questions. • Save your work at regular intervals. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 100. • No extra time is allowed for printing and collating. • The question paper is divided into four sections. Advice You are advised to allocate time to each section as follows: Section A – 40 minutes; Section B – 20 minutes; Section C – 20 minutes; Section D – 70 minutes. At the end of the examination Tie together all your printed Electronic Answer Document pages and hand them to the Invigilator. IB/G/Jun23/E10 7517/1 2 Section A You are advised to spend no longer than 40 minutes on this section. Enter your answers for Section A in your Electronic Answer Document. You must save this document at regular intervals. 0 1 0 2 Describe the process that should be followed to add an item to a circular queue implemented as a static data structure using an array. Your method should deal appropriately with any issues which could arise. [5 marks] Figure 1 shows a logic puzzle. Figure 1 The following five coloured shapes are placed on a table. 0 2 . 1 Tabitha secretly chooses one of the coloured shapes and: • tells Walter the colour of the shape she has chosen (pink, yellow or blue) • tells Lionel the type of shape she has chosen (triangle, circle or square). Lionel and Walter both know what coloured shapes are on the table. Lionel knows that Walter has been told the colour chosen by Tabitha. Walter knows that Lionel has been told the type of shape chosen by Tabitha. They do not know what the other has been told. Tabitha first asks Walter and Lionel if they know which coloured shape she has chosen. They both answer at the same time and say “No”. Tabitha then asks them again if they know which coloured shape she has chosen. They both answer at the same time and say “No” again. Tabitha asks them a third time if they know which coloured shape she has chosen and they both answer at the same time and say “Yes”. After they have both replied to Tabitha’s first question, what does Lionel now know about Tabitha’s choice because Walter said “No”? [1 mark] IB/G/Jun23/7517/1 3 0 2 . 2 After they have both replied to Tabitha’s first question, what does Walter now know about Tabitha’s choice because Lionel said “No”? [1 mark] 0 2 . 3 Which coloured shape had Tabitha chosen? [1 mark] Turn over for the next question Turn over ► IB/G/Jun23/7517/1 4 0 3 0 3 . 1 0 3 . 2 A binary tree is a type of data structure. State two characteristics that make a tree a binary tree. [2 marks] Figure 2 shows a binary tree and its representation using an array of records called Tree. Each record consists of three fields, Data, Left and Right. Figure 2 [0] Data Left Right 6 1 4 [1] 3 2 3 [2] 1 -1 -1 [3] 4 -1 -1 [4] 9 -1 -1 Figure 3 shows a subroutine that implements a binary tree search algorithm using the array Tree. The subroutine parameter, k, is the data item being searched for. The subroutine returns a Boolean value indicating if the data item being searched for is in the binary tree or not. Parts of the algorithm are missing. Figure 3 SUBROUTINE BTS(k) Current  _____1_____ WHILE Current > ____ 2_____ IF Tree[Current].Data = k THEN RETURN _____3_____ ELSEIF Tree[Current].Data < k THEN ____ 4_____ ELSE _____5_____ ENDIF ENDWHILE RETURN _____6_____ ENDSUBROUTINE