How do you find the length of the shortest word ladder from beginWord to endWord?
PICTURE THIS: DATA SPLIT
Fit on train, tune on val, report on test once.
Simple meaning
BFS on the word graph where edges are one-letter differences
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:
- 1BFS on the word
graph where edges are one-letter differences
- 2wildcard buckets like *ot/h*t/ho*
build adjacency in O(n * L^2) and BFS is O(n * L).
- 3Bidirectional BFS is a
common optimization.
- 4DFS is the wrong
tool because you need shortest unweighted distance.
- 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
BFS on the word graph where edges are one-letter differences wildcard buckets like *ot/h*t/ho* build adjacency in O(n * L^2) and BFS is O(n * L).