Heap / Priority Queuehard70 minFrontend Engineer

Table Real-Time Top-K Prioritizer

Frontend Engineer signal: heap + top-k in a virtualized analytics table context. This is a ProdMatch-owned frontend engineer drill, framed as a April 2026 Practo Dashboard UX simulation, not a copied platform question.

Company context

Practo · Dashboard UX

Freshness

April 2026

Product surface

virtualized analytics table

ProdMatch interview simulation based on product-team patterns; not a claim of a real company question.

Question

Your Dashboard UX team needs a live top-k view for rows. Each update changes an item's score. Return the current top k item IDs after each update, ordered by score desc then ID asc.

Input

Initial scores, k, and update stream [id, delta].

Output

Top-k IDs after every update.

Constraints

1 <= items <= 200000
1 <= updates <= 200000
Scores can be negative.

Concepts

render scheduling
state graphs
virtualization
heap
top-k
streaming rank

scores: [5,1,3], k=2, update [1,+5] -> [1,0]

Approach

Try framing your own approach first. The 30 seconds you think before peeking is where learning happens.

Clean Solution

Reveal the approach first.

How well did you understand?

Your rating tunes when this problem shows up again.

Common Mistakes

Use a stable tie-breaker for equal scores.
Do not sort the full stream when k is small.

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