Beginner Topic 12 of 51 Algorithms
Quick Sort
Partitioning around a pivot then sorting each side.
How it works
Pick a pivot, partition elements into smaller and larger groups, then recursively sort each side. Average O(n log n), worst O(n²) with bad pivots, in-place.
Where it is used
General-purpose sorting in many standard libraries.
Common pitfall
Poor pivot choices on sorted input; use random or median-of-three pivots.
Where it fits in the course
Quick Sort is topic 12 of 51 in Algorithms, rated Beginner. It follows Merge Sort. The next topic is Counting Sort.
Practice and explore
- Open the interactive lesson, with a mini quiz.
- Take the Algorithms quiz.
- Explore the Sorting Algorithms visualizer: Bubble, selection, insertion, merge and quick sort animated.
How to study this topic
- Read the explanation above and restate the definition in your own words.
- Open the interactive lesson and answer its mini quiz.
- Read the common pitfall, then write a short example that avoids it.
- Check your understanding in the Algorithms quiz, and revisit the topic if you miss a question.
Frequently asked questions
What is Quick Sort?
Partitioning around a pivot then sorting each side. It belongs to Algorithms and is a beginner-level topic.
Where do people use Quick Sort?
General-purpose sorting in many standard libraries.
What is the most common mistake with Quick Sort?
Poor pivot choices on sorted input; use random or median-of-three pivots.
What should I learn before this topic?
Start with Merge Sort, the topic just before it in Algorithms.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Algorithms quiz. You can also explore Sorting Algorithms in the Visual Lab.
Is Quick Sort hard to learn?
It is a Beginner topic, so it works as an entry point. If the terms are new, read the explanation twice and try the visualizer before the quiz.
How long does it take to learn Quick Sort?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Quick Sort?
Merge Sort, Counting Sort, Insertion Sort are closely connected. The full list is in the related topics section of this page.
What should I study after Quick Sort?
Continue with Counting Sort, the next topic in Algorithms.
Related topics
- Merge Sort (Algorithms)
- Counting Sort (Algorithms)
- Insertion Sort (Algorithms)
- Radix Sort (Algorithms)