How do you find critical connections (bridges) in an undirected network?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
Tarjan DFS with discovery time and low-link: an edge u-v is a bridge if v cannot reach an ancestor of u, i.e., low[v] > disc[u].
WHY — Graphs instead of guessing?
Why interviewers care about Graphs:
question about Graphs.
trade-offs, and what you would actually do on a DSA project - not buzzwords.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Tarjan DFS with discovery
time and low-link: an edge u-v is a bridge if v cannot reach an ancestor of u, i.e., low[v] > disc[u].
- 2Time is O(V+E) and
space is O(V+E).
- 3Removing each edge and
rerunning connectivity would be O(E(V+E)).
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Tarjan DFS with discovery time and low-link: an edge u-v is a bridge if v cannot reach an ancestor of u, i.e., low[v] > disc[u]. Time is O(V+E) and space is O(V+E).