Word Ladder
A hard-tier problem at 43% community acceptance, tagged with Hash Table, String, Breadth-First Search. Reported in interviews at Reddit and 24 others.
Word Ladder shows up in assessments at Reddit, Yelp, Snap, LinkedIn, TikTok, and eBay. It's rated Hard, but the 43% acceptance rate tells you it's not a pure algorithmic wall, it's a pattern recognition problem. Most candidates fail because they either brute-force permutations or don't see that this is actually a shortest-path problem in disguise. If this problem hits your live OA and you blank on the graph structure, StealthCoder solves it in seconds, invisible to the proctor.
Companies that ask "Word Ladder"
Word Ladder is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop.
Get StealthCoderWord Ladder asks you to find the shortest transformation sequence from one word to another, where each step changes exactly one letter and the intermediate word must exist in a given dictionary. The trick is recognizing this as a BFS problem on an implicit graph. The naive approach, checking all permutations of letters, explodes. Instead, you build neighbors on the fly by generating all one-letter variants of each word and checking if they're in the dictionary. Hash Table lookup is your speed gate. BFS guarantees the shortest path. Common failure: trying to precompute the full graph, which tanks memory. The winning pattern is lazy neighbor generation during traversal. StealthCoder handles the implementation details so you don't waste time debugging when time pressure hits.
Pattern tags
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Word Ladder recycles across companies for a reason. It's hard-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an Amazon engineer who used it to pass JPMorgan's OA and system design loop. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Word Ladder interview FAQ
Why do most people fail Word Ladder in an interview?+
They see it as a string problem and try character permutations. They miss the BFS insight. Once you frame it as shortest-path-in-a-graph, the solution becomes straightforward: generate neighbors via one-letter substitution, check against the dictionary hash table, run BFS. The pattern switch is the whole game.
Is Word Ladder still asked at FAANG companies?+
Yes. It appears across 25 reported companies including LinkedIn, TikTok, and eBay. It's not the absolute most frequent ask, but it's common enough that you can't skip it. The companies asking it tend to care about graph thinking and optimization under constraints.
What's the actual trick to Word Ladder?+
Lazy neighbor generation. Don't precompute a full adjacency list. Instead, for each word during BFS, iterate through all positions and generate one-letter variants, then check if each variant is in a hash table of the dictionary. This keeps memory linear and avoids timeout on large dictionaries.
How do Hash Table, String, and BFS connect in this problem?+
Hash Table gives you O(1) dictionary lookups when checking if a generated word variant is valid. String work is the one-letter substitution loop. BFS is the traversal that guarantees the shortest transformation sequence. Together, they form an efficient graph search without explicit edge storage.
How long should Word Ladder take to code in an interview?+
If you recognize the BFS pattern, 15 to 20 minutes for a correct solution. If you don't see it upfront, you'll thrash. That's where the Hard rating bites. Have the neighbor-generation logic crisp in your head before you start typing.
Want the actual problem statement? View "Word Ladder" on LeetCode →