Technical Screen

A Deep Dive on the Classic Orderbook Problem

CitadelSoftware Engineer · Intern · Technical Screen · Sep 2026

This was my second round for the Citadel SWE intern process. The technical part was the classic orderbook problem. The question was the classic orderbook problem. Problem description: Design and implement an order book data structure that maintains order records containing the exchange name, price, quantity, and side (bid or ask). It needs to support three core APIs: add(exchange, price, quantity…

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