Intervalshard70 minFull Stack Developer

Realtime Capacity Interval Planner

Full Stack Developer signal: line sweep + interval merge in a realtime collaboration context. This is a ProdMatch-owned full stack engineer drill, framed as a April 2026 Postman Realtime Platform simulation, not a copied platform question.

Company context

Postman · Realtime Platform

Freshness

April 2026

Product surface

realtime collaboration

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

Question

Plan capacity for realtime collaboration. Given reservation intervals with requested units, return the minimum capacity needed and all time ranges where capacity crosses a critical threshold.

Input

Intervals [start, end, units] and threshold.

Output

Peak capacity and merged high-pressure intervals.

Constraints

1 <= intervals.length <= 200000
Intervals are half-open: [start, end).
Timestamps fit in signed 32-bit integers.

Concepts

workflow graphs
API pagination
cache invalidation
line sweep
interval merge
capacity planning

[[1,4,3],[2,5,4]], threshold=6 -> peak=7, hot=[[2,4]]

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

Be explicit about whether touching endpoints overlap.
Process end events before start events for half-open intervals.

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