What Is Top K?
The “Top K” problem refers to determining the top-k elements with the highest frequencies or relevance scores from vast, rapidly changing data streams. In modern real-time systems — such as e-commerce platforms, social media, and streaming services — it’s vital to quickly identify the most relevant items or events. Real-world examples include:
- Trending Twitter hashtags rapidly shifting based on tweet volume
- Most-watched Netflix movies updating hourly across regions
- Top Amazon products ranking sales in real time
- Popular YouTube videos updating hourly based on view velocity
The “Top K” approach is essential for use cases like: