OpenAI

OpenAI

Leading AI research laboratory developing state-of-the-art foundation models like GPT-4.

5 Rounds ~21 Days Very Hard
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The Interview Loop

Recruiter Screen (30 min)

Standard fit check, behavioral questions, and resume overview.

Technical Loop (3-4 Rounds)

Deep dive into domain knowledge, coding, and system design.

Interview Question Bank

Machine Learning Engineer • Coding • medium

Write a Byte-Pair Encoding (BPE) tokenizer from scratch. Given a corpus of text and a target vocabulary size, implement the training and tokenization functions.

#String Manipulation #Data Structures #NLP
Practice
Machine Learning Engineer • Coding • hard

Implement an autoregressive generation loop with KV Caching. Assume a simplified transformer block is provided.

#Memory Management #Transformers #PyTorch
Practice
Machine Learning Engineer • Coding • medium

Implement a simplified Byte Pair Encoding (BPE) tokenizer. Given a corpus of text and a target vocabulary size, write a function to find the most frequent adjacent pair of characters or tokens and merge them.

#Strings #Hash Maps #NLP
Practice
Machine Learning Engineer • Coding • hard

Write a simple Autograd engine for scalar values from scratch. Implement the forward and backward passes for addition and multiplication.

#Calculus #Graphs #Object-Oriented Programming
Practice
Machine Learning Engineer • Coding • medium

Design a data structure for efficient KV cache eviction in an LLM serving engine. It must support O(1) inserts, O(1) lookups, and evict the least recently used sequence block.

#Data Structures #Linked Lists #Hash Maps
Practice
Machine Learning Engineer • Coding • hard

Write a function to perform matrix multiplication of two large 2D arrays. Optimize it for cache locality using block matrix multiplication (tiling).

#C++ #Performance Optimization #Computer Architecture
Practice
Machine Learning Engineer • Coding • medium

Implement Beam Search decoding for a language model given a function that returns the next-token probabilities.

#Search Algorithms #Heuristics #NLP
Practice
Machine Learning Engineer • Coding • medium

Implement a Token Bucket rate limiter for the OpenAI API. It needs to handle multiple users, support concurrent requests, and be highly performant.

#Concurrency #System Design #Data Structures
Practice
Machine Learning Engineer • Coding • medium

Given a Directed Acyclic Graph (DAG) representing a computation graph of ML operations, write an algorithm to schedule the operations on a fixed number of parallel workers to minimize total execution time.

#Graphs #Scheduling #Topological Sort
Practice
Machine Learning Engineer • Coding • hard

Implement a mock distributed parameter server. Write the worker code that computes gradients and the server code that aggregates them and updates weights, communicating via queues.

#Concurrency #Distributed Systems #Python
Practice
Machine Learning Engineer • Coding • hard

Implement the Aho-Corasick algorithm to efficiently search for a large dictionary of toxic words within a streaming text generation output.

#Trees #Trie #String Matching
Practice
Machine Learning Engineer • Coding • medium

Given a list of text highlight spans (start_index, end_index) from multiple human labelers, write a function to merge all overlapping spans into a consolidated list of highlighted regions.

#Arrays #Sorting
Practice

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Senior Engineer

Focuses on core competencies, system constraints, and clear communication.

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