Graphsmedium45 minFrontend Engineer

Experiment Evidence Path Finder

Frontend Engineer signal: shortest path + weighted graph in a A/B experiment console context. This is a ProdMatch-owned frontend engineer drill, framed as a March 2026 PayPal Experimentation simulation, not a copied platform question.

Company context

PayPal · Experimentation

Freshness

March 2026

Product surface

A/B experiment console

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

Question

In A/B experiment console, 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

render scheduling
state graphs
virtualization
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

Timeline Dependency DAG Recoverymedium Timeline Evidence Path Finderhard Autocomplete Dependency DAG Recoveryhard