Interview questions

LRU Cache

Implement an LRUCache that supports O(1) average-time get(key) returning the value or -1 and put(key, value) which inserts or updates a key and, if capacity…

Companies: Adobe, Amazon, Anthropic, Apple +29

Data Structure Design · Design · Doubly-Linked List · Hash Table

Last reported Oct 2026

All Paths From Source to Target

Given a DAG as adjacency lists, enumerate all possible paths from source node 0 to target node n−1 and return each path as a list…

Companies: Bloomberg

Last reported Oct 2026

Autocomplete User Search

Build an autocomplete input component that fetches and displays matching users by name or email as the user types, using a provided `queryUsers` API, with…

Companies: Kikoff

Last reported Oct 2026

On-Call Rotation Schedule

Given an on-call rotation schedule with each person's name, start timestamp, and end timestamp, return a non-overlapping rotation table showing all people on-call during each…

Companies: Google

Last reported Oct 2026

Top N Stocks by Trading Volume

Given a stream of stock trade notifications, each containing a ticker symbol and a volume, track the cumulative volume traded for each stock and efficiently…

Companies: Bloomberg

Last reported Oct 2026

Round Robin Algorithm: Debugging and Testing

Debug and complete the implementation of a traffic router using the round robin algorithm. Identify and fix any bugs in the existing code, ensure all…

Companies: Brex, DoorDash, Paxos

Last reported Oct 2026

Implement a thread-safe rate limiter

Design a rate limiting system that can control the number of requests a user or client can make within a specified time window, preventing abuse…

Companies: Amazon, Apple, Cohesity, Coupang +3

Last reported Oct 2026

Implement a useQuery Hook in React

Implement a custom React hook called useQuery that manages asynchronous data fetching via a promise. The hook should handle loading, success, and error states for…

Companies: Perplexity

Last reported Oct 2026

Nested List Weight Sum II

Given a nested list of integers, compute the sum where each integer is weighted by the reverse of its depth (elements deeper in the nesting…

Companies: LinkedIn, Meta

Breadth-First Search · Depth-First Search · Stack

Last reported Oct 2026

All O`one Data Structure

Design a data structure that supports incrementing and decrementing string counts (removing keys when their count drops to zero) and can return any key with…

Companies: Atlassian, LinkedIn, Meta, Microsoft +2

Design · Doubly-Linked List · Hash Table · Linked List

Last reported Oct 2026

Design a Redundant Feed Arbitrator Class

Design a class that consumes messages from multiple redundant feeds carrying the same sequenced content and republishes a single clean, ordered, deduplicated stream where a…

Companies: Citadel

Last reported Oct 2026

Design an Ordered Stream

Maintain an array-backed stream of n (id, value) pairs arriving out of order and, on each insert, return the largest contiguous chunk of values starting…

Companies: Citadel

Last reported Oct 2026

Group Anagrams

Group the input strings into lists of anagrams — i.e., strings that contain the same multiset of letters — and return the groups in any…

Companies: Amazon, Apple, Arize Ai, Bloomberg +14

Array · Hash Table · Sorting · String

Last reported Oct 2026

Path Sum IV

Given a list of three-digit integers encoding a binary tree (hundreds=d epth, tens=position in level, ones=node value), compute the sum of all root-to-leaf path sums…

Companies: Grab

Last reported Oct 2026

Top K Frequent Words

Count word frequencies and return the k most frequent words sorted by descending frequency, breaking ties by lexicographical order. The core challenge is combining frequency…

Companies: Apple, Microsoft, Oracle, Robinhood

Array · Bucket Sort · Counting · Hash Table

Last reported Oct 2026

LinkedIn Connection Distance

Find the shortest path (degree of separation) between two user profiles in a social network graph. How do you handle the search space explosion caused…

Companies: LinkedIn

Last reported Oct 2026

Count Occurrences of an Element in a Sorted Array

Given a sorted array of n elements, possibly with duplicates, find the number of occurrences of a target element.

Companies: Meta

Last reported Oct 2026

Implement a Reusable Toast Component in React

Build a reusable Toast component in React based on provided UI specs and a demo video. The component should match the given design and replicate…

Companies: OpenAI

Last reported Oct 2026

Merge Intervals

Given a list of intervals, merge all overlapping (including touching endpoints) intervals and return the minimal set of non-overlapping intervals that cover them. Key pattern…

Companies: Amazon, Antithesis, Apple, Atlassian +16

Array · Quicksort · Sorting

Last reported Oct 2026

Design a File Search and Directory Traversal System

Design and implement a file search system that can traverse directory structures and locate files based on various criteria. The solution should incorporate object-oriented…

Companies: Amazon, Anduril, Atlassian, Google +1

Last reported Oct 2026

Find the Kth Largest Integer in the Array

Given an array of non‑negative integers encoded as decimal strings (no leading zeros) and an integer k, return the k-th largest numeric value treating duplicates…

Companies: Evernorth, Meta, Spotify

Last reported Oct 2026

Koko Eating Bananas

Find the minimum integer eating speed k such that the total hours required (sum over piles of ceil(piles[i]/k)) is ≤ h; because the required hours…

Companies: Amazon, Bloomberg, Coupang, DoorDash +6

Array · Binary Search

Last reported Oct 2026