Bubble sort – practice for Years 7–9

Sample questions on Bubble sort with the right answer and a worked solution, from easy to hard. In the Pickles Academy app a child gets new questions of the same kind every time, so they can't just learn the answers by heart.

Subject

Computing

Year

Years 7–9

Curriculum area

Information systems

Question types: Bubble sort

Sample questions

1. Question 1 Easy

   Bubble sort goes through the list from left to right, compares each two neighbouring numbers and swaps them when the left one is bigger. It repeats such passes while it still swaps something. How many swaps does it make to sort 13, 9, 1, 7 from smallest to largest?

   Show the solution

   Answer: 5

   How it works: Swaps in each pass: 3 + 2 + 0 = 5.

2. Question 2 Normal

   Bubble sort goes through the list from left to right, compares each two neighbouring numbers and swaps them when the left one is bigger. It repeats such passes while it still swaps something. How many swaps does it make to sort 17, 2, 14, 1, 10, 18 from smallest to largest?

   Show the solution

   Answer: 7

   How it works: Swaps in each pass: 4 + 2 + 1 + 0 = 7.

3. Question 3 Hard

   Bubble sort goes through the list from left to right, compares each two neighbouring numbers and swaps them when the left one is bigger. It repeats such passes while it still swaps something. What does the list 17, 2, 14, 1, 10, 18 look like after the first pass?

   1. A) 2, 17, 14, 1, 10, 18
   2. B) 2, 1, 10, 14, 17, 18
   3. C) 2, 14, 1, 10, 17, 18
   4. D) 1, 2, 10, 14, 17, 18
   5. E) 18, 17, 2, 14, 1, 10
   Show the solution

   Answer: C) 2, 14, 1, 10, 17, 18

   How it works: After pass 1: 2, 14, 1, 10, 17, 18.

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