Robinhood Coding Interview Questions

You are given a list of service definitions describing a directed acyclic graph (DAG) of microservices. Each definition has the format <service_name>=<dep1>,<dep2>,...…

The round is one graded task with one reported follow-up. Secure Part 1 first; one report has the interviewer saying they do…

Robinhood's referral program lets existing users refer new users to the platform. Given two parallel arrays — rh_users (referrers) and new_users (the…

You are given a list of API call strings, each prefixed with a sequential request_id. There are 5–6 request types: 1. REGISTER…

Given a list of strings (e.g., ['a', 'bb', 'cccccc', 'd', 'eeeee', 'f']), an integer maxRows (e.g., 3), an integer screenWidth (e.g., 6),…

Given a string (ranging from a short sentence to an entire book paragraph), extract all words, count their frequencies, and return the…

You are given a list of courses (or services) with prerequisite/dependency relationships. The core task is to produce a valid topological ordering…

Implement a one-page iOS app (in Xcode, live coding) containing a UITableView with 50 rows. Each row displays a timer counter. Requirements:…

You are given a grid of rectangular blocks (e.g., a 3×3 HTML grid) and an empty class skeleton. Implement a chainable API…

Case study: design a machine learning model to detect fraud (specifically fraud account detection). You are given an open-ended scenario and must…

Build an interactive weekly calendar UI in React. The grid has 7 days as rows (or columns, per mockup) and hourly time…

Given a web application, design how to build it on the front-end side. The candidate is expected to architect the front-end of…

Given a singly linked list, first reverse it entirely (e.g., 1→2→3→4 becomes 4→3→2→1). Follow-up: reverse every two…

Implement a multi-part event logger in JavaScript/browser environment. The problem has four progressive parts: Part 1 – DOM Querying & Click Handlers:…

You are given a Finder class with the following methods: find(idx) — selects the block at the given index; color(newColor) — applies…

Build a React component implementing an extended todo list application. Requirements include: component reuse (breaking the UI into reusable sub-components), state management…

Implement a standard Union-Find (Disjoint Set Union, DSU) data structure. The problem is described as the most fundamental DSU template question —…

Given a pre-built framework for an Android-based stock trading system, implement two specified methods within the provided class/interface structure. The problem is…

Design a calendar application similar to Google Calendar. The problem involves event management (creating, updating, deleting events), scheduling logic (handling time zones,…

Implement a 'retryer' mechanism — a utility that automatically retries a given operation (e.g., a function call) upon failure, up to a…

Implement a placeOrder(ticker: String) method inside a stock manager class. The method accepts stock ticker names (e.g., AAPL, GOOGLE, META). A provided…

Design and implement a string validation function with security-oriented constraints. The function must correctly validate input strings according to defined rules (similar…

Given a collection of intervals, merge all overlapping intervals and return the resulting list of non-overlapping intervals. This is the classic LeetCode…

Given a stream of Kafka message offset commits, determine the committed offset state. In Kafka's consumer model, messages are processed and their…

Design a data structure that satisfies specific constraints (similar in structure to a LeetCode Medium-Hard constrained data structure problem). Beyond the core…

You are given two tables: 1. user_info (id, shard, name, state, …) — current user profile. The join key is the composite…