Intermediate~2h
Heap & Priority Queue in Data Structures & AlgorithmsInterview Readiness Check
Top-K elements, merge K sorted structures, median of a stream — when you need the max/min fast.
min heapmax heaptop-Kk-th largestmerge k sortedmedian stream
Learning path
Try a sample question
Find the k largest elements from a stream of 10M numbers. Which approach is O(n log k) and uses O(k) space?
A.Min-heap of size k — for each number, if it's larger than the heap's minimum, pop the min and push the new number. Heap always contains the k largest seen.
B.Sort all numbers descending, take first k — O(n log n), O(n) space
C.Max-heap of all numbers, pop k times — O(n + k log n)
D.QuickSelect to find the k-th largest, then filter — O(n) average
Sign up free to take the full check and see the answer with an explanation.
What this module tests
- Conceptual understanding of heap & priority queue fundamentals
- Trade-offs and design decisions in real system scenarios
- min heap and max heap — applied knowledge
- Interview-style reasoning and explanation quality
Free to start
Take the Heap & Priority Queue check →
10 questions · Dimension scoring · AI coach feedback · Shareable result
Test your knowledge — free →No credit card · Takes 10–15 min
Frequently asked questions
- What does the Heap & Priority Queue check test?
- The check covers top-k elements, merge k sorted structures, median of a stream — when you need the max/min fast. Questions span beginner to advanced difficulty and test both conceptual understanding and practical trade-off reasoning.
- What keywords should I know for Heap & Priority Queue?
- Key concepts include: min heap, max heap, top-K, k-th largest, merge k sorted, median stream. These frequently appear in data structures & algorithms interviews at product and infrastructure companies.
- How many questions are in the check?
- Each check has 10 questions — a mix of MCQ and short-answer. You get scored by dimension (e.g., scalability, consistency) so you know exactly where to focus.
- How long does it take to study Heap & Priority Queue?
- Most engineers spend around 2 hours on this module. The check itself takes about 10–15 minutes. You can retake it up to 3 times per day.
- What prerequisite knowledge do I need before Heap & Priority Queue?
- Heap & Priority Queue builds on Trees: BFS & Level Order. Complete those first for the best results.
- Is min heap, max heap, top-K covered?
- Yes. The Heap & Priority Queue module covers min heap, max heap, top-K among other key concepts. The check includes questions that reflect real data structures & algorithms interview patterns.