Sorting and searching
Choosing the right algorithm can be the difference between a million steps and twenty.
Part of your national curriculum
- Algorithms and programming: Understand several key algorithms, including those for sorting and searching, and use logical reasoning to compare their utility
Lesson overview
What you'll learn in this lesson
Understand several key algorithms, including those for sorting and searching, and use logical reasoning to compare their utility
Key learning points
- • Linear versus binary search
- • Bubble sort
- • Comparing utility
This lesson at a glance
- 28 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Sorting and searching
Choosing the right algorithm can be the difference between a million steps and twenty.
In a nutshell
Understand several key algorithms, including those for sorting and searching, and use logical reasoning to compare their utility
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · Linear versus binary search
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
Linear versus binary search
Linear search checks each item in turn and works on any list. Binary search repeatedly halves a sorted list, so a million items takes about twenty checks instead of a million.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Bubble sort
Compare neighbouring pairs and swap them if they are the wrong way round, repeating until a full pass makes no swaps. Simple to write, slow on long lists.
Quick check
Part 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · Comparing utility
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
Comparing utility
The best algorithm depends on the situation. Sorting first is only worth it if you will search the list many times.
Quick check
Part 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ first is only worth it if you will search the list many times.
Challenge round
Part 15 of 17
Game · Recall cards
Binary search requires the list to be…
Card 1 of 3
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Sorting and searching
3 questions, marked with the reasoning shown. No timer.
1. Binary search requires the list to be…
2. Roughly how many checks does binary search need for a million items?
3. Bubble sort finishes when…
Lesson round-up
Part 17 of 17
Lesson round-up
Ready when you are
Quiz score
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Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 17 · Watch & discover
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Understand several key algorithms, including those for sorting and searching, and use logical reasoning to compare their utility