Technical Screen

File Deduplication, Size Checks, and Reference Counts

CitadelSoftware Engineer · Intern · Technical Screen · Sep 2026

My first Citadel SWE interview. The interviewer was on the hedge fund side. I gave a brief introduction. Before I had a chance to tell the behavioral stories I'd prepared, he went straight into technical questions. The interview was basically 100% coding and system design. Problem: Suppose a file system contains files with identical contents. For example, /a/b/c.txt and /a/b/e.txt both contain th…

Shared by a candidate · reported Sep 2026. Interview formats change; use it as a guide, not a script.