Heap / Priority Queuehard70 minPlatform Engineer

Tenancy Real-Time Top-K Prioritizer

Platform Engineer signal: heap + top-k in a multi-tenant quota context. This is a ProdMatch-owned platform engineer drill, framed as a April 2026 CRED Cloud Platform simulation, not a copied platform question.

Company context

CRED · Cloud Platform

Freshness

April 2026

Product surface

multi-tenant quota

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

Question

Your Cloud Platform team needs a live top-k view for tenants. 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

build DAGs
tenant quotas
artifact caching
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.

Next Similar Problems

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