Graphshard70 minBackend Engineer

Inventory Evidence Path Finder

Backend Engineer signal: shortest path + weighted graph in a flash-sale inventory context. This is a ProdMatch-owned backend engineer drill, framed as a May 2026 Cars24 Marketplace Infra simulation, not a copied platform question.

Company context

Cars24 · Marketplace Infra

Freshness

May 2026

Product surface

flash-sale inventory

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

Question

In flash-sale inventory, entities are connected by weighted evidence edges. For each query, find the least-cost evidence path from source to target while avoiding blocked entities.

Input

Weighted graph, blocked set, and q source-target queries.

Output

Minimum cost per query, or -1 if unreachable.

Constraints

1 <= nodes <= 100000
1 <= edges <= 300000
1 <= queries <= 100000
All weights are non-negative.

Concepts

idempotency
queues
rate limiting
shortest path
weighted graph
retrieval quality

0-1 cost 2, 1-2 cost 3, query 0->2 -> 5

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

Mark visited when enqueueing, not after repeated dequeue.
Do not ignore disconnected components if the product surface can have them.

Next Similar Problems

Idempotency Dependency DAG Recoverymedium Idempotency Evidence Path Finderhard Ledger Dependency DAG Recoveryhard