Graphsmedium45 minSecurity Engineer

Threat Dependency DAG Recovery

Security Engineer signal: topological sort + cycle detection in a threat intel graph context. This is a ProdMatch-owned security engineer drill, framed as a March 2026 Zomato Security Platform simulation, not a copied platform question.

Company context

Zomato · Security Platform

Freshness

March 2026

Product surface

threat intel graph

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

Question

You own threat intel graph for a Security Engineer loop. Given indicators and directed dependencies between them, return a valid execution order. If a cycle exists, return an empty list and identify that the rollout is blocked.

Input

n nodes labelled 0..n-1 and dependency pairs [before, after].

Output

A valid order of all nodes, or [] when dependencies contain a cycle.

Constraints

1 <= n <= 200000
0 <= dependencies.length <= 400000
The graph may be disconnected.

Concepts

attack graphs
policy tries
anomaly detection
topological sort
cycle detection
dependency graph

indicators: 4, deps: [[0,1],[0,2],[2,3]] -> [0,1,2,3] or [0,2,1,3]

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

Attack Dependency DAG Recoverymedium Attack Evidence Path Finderhard Policy Dependency DAG Recoveryhard