Heap / Priority Queuehard70 minDevOps / SRE Engineer

Logs Real-Time Top-K Prioritizer

DevOps / SRE Engineer signal: heap + top-k in a log compaction context. This is a ProdMatch-owned devops sre drill, framed as a April 2026 Wingify Observability simulation, not a copied platform question.

Company context

Wingify · Observability

Freshness

April 2026

Product surface

log compaction

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

Question

Your Observability team needs a live top-k view for spans. 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

blast-radius graphs
alert dedupe
rolling windows
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

Incident Real-Time Top-K Prioritizerhard Deploy Real-Time Top-K Prioritizerhard Capacity Real-Time Top-K Prioritizerhard