What is a Cyclic vs Acyclic Graph?

0-2 years experience

1. 1We have a small list of tasks where some depend on others. How would you quickly check if the dependency list contains a cycle before we run them?
2. 2If you represent a family tree as a directed graph and accidentally add a parent link that creates a loop, what problems would that cause when you try to traverse it?

2-5 years experience

1. 1Our build system started failing after a new module was added. Walk me through how you'd debug whether a cyclic dependency introduced the failure.
2. 2You need to convert a legacy data‑flow graph that may contain cycles into an execution order. How would you handle the cycles you discover?

5-8 years experience

1. 1Design a service that processes jobs with arbitrary dependencies across microservices. How would you ensure the dependency graph stays acyclic at scale?
2. 2What are the performance trade‑offs between using DFS recursion versus Kahn’s algorithm for cycle detection in a graph with millions of nodes?
3. 3If edges can be added dynamically to a large directed graph, how would you efficiently detect whether a new edge creates a cycle?

8+ years experience

1. 1Our organization is migrating from a monolithic pipeline that uses a cyclic graph to a new DAG‑based orchestration platform. What architectural changes and migration steps would you propose?
2. 2When multiple teams own parts of a global dependency graph, how would you enforce acyclicity and prevent accidental cycles over time?
3. 3Discuss a long‑term maintenance strategy for a distributed system that relies on an acyclic graph for data lineage, considering versioning and backward compatibility.