Interview questions

Design a Time-Windowed GPU Credit Ledger

Companies: OpenAI

Distributed Transactions & Idempotency · System Design Fundamentals

Last reported Aug 2026

Clarify a Machine Topology Coding Task

Companies: OpenAI

Last reported Aug 2026

Token Bucket Rate Limiter (Go Code Review)

Review a Go implementation of a token bucket rate limiter. Identify issues related to uninitialized maps, concurrency race conditions on shared data structures, and suboptimal…

Companies: Google

Last reported Aug 2026

Serialize and Restore an In-Memory Key-Value Store

Companies: OpenAI

Parsing & Interpreters

Last reported Aug 2026

Reuse Work Across Multiprocess Image Pipelines

Companies: Anthropic

Last reported Aug 2026

Implement a Set with Readable Snapshots

Companies: OpenAI

Data Structure Design

Last reported Aug 2026

Fix Broken Recurring Payments in a Billing Platform

Given a full-stack billing application and an AI agent, reproduce and diagnose recurring payment bugs across the codebase. Identify the root causes and submit the…

Companies: Amazon

Last reported Aug 2026

Implement a Polling System

Design and implement a full-stack polling system that allows users to create polls and share unique links. Voters should only be able to cast a…

Companies: Upstart

Last reported Aug 2026

Service Dependency Notification System

Given a Service Network represented as a DAG where services depend on other services, implement a notification system using FastAPI that alerts a service when…

Companies: Snapchat

Last reported Aug 2026

Implement meeting-room availability and reservation

Design a Meeting Room Scheduler data structure that supports two operations: checkAvailability(startTime, endTime) which returns a list of available meeting rooms for the given…

Companies: Loop, Uber

Last reported Jul 2026

Interval Addition and Next Interval Lookup

Given a set of intervals, implement operations to add new intervals (merging overlapping ones as needed) and find the next interval for a given interval…

Companies: LinkedIn

Last reported Jul 2026

Minimum Robots to Capture Sara

Given a tree of N outposts (2 ≤ N ≤ 7×10⁴) connected by N-1 bidirectional tunnels where leaf nodes are exits, determine the minimum number…

Companies: LinkedIn

Last reported Jul 2026

Rate Limiting

Design and implement a rate limiting system that controls the frequency of requests from users or services. Use AI tools to assist in building the…

Companies: Visa

Last reported Jul 2026

Token Bucket Rate Limiter (Java Code Review)

Review a buggy Java implementation of a rate limiter using the Token Bucket algorithm, where tokens are refreshed at a fixed rate. Identify the bugs…

Companies: Cloudflare

Last reported Jul 2026

Debug and Extend a JSON File Parser for a Finance Calculator

Given a JSON file parser for a finance-related calculator, identify and fix existing bugs then implement new features such as additional data types and modified…

Companies: Nubank

Last reported Jul 2026

Debug a Python Job Scheduler: Failed Jobs Stuck in PENDING and Async Jobs Never Run

Companies: OpenAI

Concurrency · Debugging

Last reported Jul 2026

Indexed Vector as a Linked List with Checkpoints Every k Nodes

Companies: OpenAI

Data Structure Design · Linked Lists

Last reported Jul 2026

Design First-Fit and Best-Fit Memory Allocation

Companies: OpenAI

Memory Management · Testing & Quality

Last reported Jul 2026

Batch-Apply Pillow Image Transforms, Then Parallelize: Processes vs Threads

Companies: Anthropic

Concurrency · Programming Languages

Last reported Jul 2026

Function-Call LRU Cache: Argument Key Generation and Crash Recovery from a Log

Companies: Anthropic

Data Structure Design · Database Internals

Last reported Jul 2026

Maze Pathfinding Algorithm

Implement an algorithm to find a path from a start node to an end node in a 2D array representing a maze. The solution should…

Companies: Meta

Last reported Jul 2026