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

Frontend Engineer • Coding • hard

Write a function to parse and render a continuous stream of Markdown text. How do you handle incomplete Markdown tokens (e.g., a code block that has started with '```' but hasn't closed yet)?

#Parsing #String Manipulation #Edge Cases
Practice
Frontend Engineer • Coding • medium

Write a function to deeply merge two JavaScript objects. It should handle nested objects, arrays, and edge cases like null or undefined.

#Recursion #Data Structures #Type Checking
Practice
Frontend Engineer • Coding • medium

Implement an LRU (Least Recently Used) Cache class in JavaScript. It should have `get(key)` and `put(key, value)` methods, both operating in O(1) time complexity.

#Data Structures #Hash Maps #Linked Lists
Practice
Frontend Engineer • Coding • medium

Write a function that takes a string of HTML and returns true if the tags are properly balanced and nested, and false otherwise.

#Stacks #String Parsing #Regex
Practice
Frontend Engineer • Coding • easy

Write a function to traverse the DOM tree starting from a given node and return an array of all text nodes that match a specific regular expression.

#DOM API #Tree Traversal #Recursion
Practice
Frontend Engineer • Coding • hard

Implement a function that schedules tasks with a maximum concurrency limit. It should take an array of functions (returning promises) and a concurrency number.

#Promises #Concurrency #Queues
Practice
Frontend Engineer • Coding • medium

Write a function to find the shortest path between two DOM elements in the DOM tree (i.e., finding their lowest common ancestor and the path to it).

#DOM API #Tree Traversal #Pointers
Practice
Frontend Engineer • Coding • hard

Write a function to serialize a DOM tree into a JSON object, and another function to deserialize that JSON object back into a DOM tree.

#DOM API #Serialization #Recursion
Practice

Difficulty Radar

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Meet Your Interviewers

The "Standard" Interviewer

Senior Engineer

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

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Unwritten Rules

Think Out Loud

Always explain your thought process before writing code or drawing architecture.

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