A-LevelComputer ScienceData StructuresOct/Nov 2022Paper 4 Q321 Marks
A binary tree consists of nodes. Each node has 3 integer values: a left pointer, data and a right pointer. The binary tree is stored using a global 2D array. The pseudocode declaration for the array is: DECLARE ArrayNodes : ARRAY[0:19, 0:2] OF INTEGER For example: • ArrayNodes[0, 0] stores the left pointer for the first node. • ArrayNodes[0, 1] stores the data for the first node. • ArrayNodes[0, 2] stores the right pointer for the first node. -1 indicates a null pointer, or null data.
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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