DRW Coding Interview Questions
25 DRW coding interview problems with full optimal solutions — 8 easy, 12 medium, 5 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an DRW interviewer values, and a FAQ section.
Showing 3 problems of 25
- #3mediumvery frequently asked
3. Longest Substring Without Repeating Characters
DRW uses this problem to test the sliding-window pattern — the same technique that powers rolling-window deduplication on market-data feeds and tick-data deduplication in low-latency pipelines. Getting to O(n) with a single hash-map pass is required; naive O(n²) solutions are rejected on sight.
- #146mediumvery frequently asked
146. LRU Cache
DRW uses LRU Cache because low-latency market-data systems rely on exactly this design: a bounded cache of recently-seen instrument snapshots, where the stale entry is evicted on each new quote. O(1) get and put are non-negotiable — the interviewer will ask for the doubly-linked-list proof.
- #295mediumvery frequently asked
295. Find Median from Data Stream
Running median over a live stream is a first-class problem at DRW: median bid-ask spread, median fill latency, median position size across strategies. The two-heap technique gives O(log n) insertion and O(1) query. DRW will ask for the Fenwick tree variant when values are bounded integers.