Unit 6: B2 Programming

Topic 6.4: Algorithms and efficiency Questions

Practice 20 exam-style questions for IB Computer Science Topic 6.4. Review the question stems below, then unlock the full Question Bank to access markschemes, model answers, and AI grading.

1Define1 mark
2026
Define what Big O notation describes.
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2Determine2 marks
2026
Determine the Big O complexity of a loop over n elements containing another loop over the same n elements.
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3State2 marks
2026
State the Big O complexity of accessing an array element by index, and of scanning a whole array.
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4Determine2 marks
2026
Determine how the time taken by an O(n squared) algorithm changes when the input triples.
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5Determine2 marks
2026
Determine the maximum comparisons binary search needs on a list of one million items.
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6Explain3 marks
2026
Explain why the inner loop of a bubble sort can stop one position earlier on each pass.
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7Construct4 marks
2026
Write a Java method for a linear search that returns the index of a target, or -1 if it is absent.
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8Explain4 marks
2026
Explain why space complexity matters as well as time complexity.
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9Construct4 marks
2026
Write a Python program that performs a selection sort on a list called values.
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10Outline3 marks
2026
Outline how a binary search works.
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11Explain3 marks
2026
Explain why the midpoint should be calculated as low + (high − low) DIV 2 in some languages.
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12Choose1 mark
2026
Choose the requirement binary search places on the data.
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13State2 marks
2026
State the Big O complexity of linear search and of binary search.
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14Determine2 marks
2026
Determine how many extra comparisons binary search needs if that list grows to two million.
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15Construct4 marks
2026
Write a Python function for a binary search on a sorted list, returning the index of the target or -1 if it is absent.
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16Determine2 marks
2026
Determine the list after one complete pass of a selection sort on [5, 2, 9, 1].
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17Determine1 mark
2026
Determine the Big O complexity of a single loop over an array of n elements.
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18Suggest4 marks
2026
Suggest when a linear search is the better choice despite its worse complexity.
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19Determine3 marks
2026
Determine the total cost of sorting a list of n items and then binary searching it once, compared with a single linear search.
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20Choose1 mark
2026
Choose the complexity of binary search on a sorted array.
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