Interview questions

Standard leetcode style question, with AI available in one interview

Companies: Meta

Last reported Mar 2026

Finding Duplicate Lines Across Multiple Files

Write a program that identifies and returns duplicate lines (records) that appear across multiple input files. The solution should efficiently handle large files and provide…

Companies: Meta

Last reported Feb 2026

Implement crawler and file deduplication

Companies: Anthropic

API Integration & HTTP Clients · Concurrency

Last reported Feb 2026

Thread-Safe Lottery System

Design and implement a thread-safe lottery system that supports adding/removing users with equal weights and selecting random winners. The system must handle concurrent…

Companies: Apple

Last reported Feb 2026

Credit Card Validation

Implement a function to validate credit card numbers using the Luhn algorithm. The function should return true if the credit card number is valid, false…

Companies: Capital One

Last reported Feb 2026

Find All Possible Recipes from Given Supplies

Given recipes whose ingredients may include other recipes and an initial set of supplies, determine which recipes can be produced; the core challenge is dependency…

Companies: Amazon, Google, Tesla

Array · Directed Acyclic Graph · Graph Theory · Hash Table

Last reported Feb 2026

Max Consecutive Ones II

Given a binary array, find the maximum length of a contiguous subarray of 1s you can get by flipping at most one 0 to 1…

Companies: Bloomberg, Snapchat

Last reported Feb 2026

Partition to K Equal Sum Subsets

Determine whether an array of up to 16 small positive integers can be split into k non-empty subsets whose sums are equal. This is a…

Companies: Amazon

Last reported Feb 2026

Split Array Largest Sum

Split the array into k non-empty contiguous subarrays so that the maximum subarray sum is as small as possible, and return that minimized largest sum…

Companies: Amazon, Google, Microsoft, Pinterest +2

Array · Binary Search · Dynamic Programming · Greedy

Last reported Feb 2026

Minimum Cost to Convert String II

Given source and target strings and a list of allowed substring → substring replacement rules with costs, compute the minimum total cost to transform source…

Companies: Microsoft

Last reported Feb 2026

Shortest Path Algorithm Implementation

Implement the Floyd-Warshall algorithm to find shortest paths between all pairs of vertices in a weighted graph.

Companies: Microsoft

Last reported Feb 2026

Candy Crush

Given an m×n board of integer "candies," repeatedly find and remove any horizontal or vertical runs of ≥3 identical candies, let the remaining candies fall…

Companies: Meta, Microsoft, Roblox

Array · Matrix · Simulation · Two Pointers

Last reported Feb 2026

Minimum Costs Using the Train Line

Compute the minimum cost to travel along a train line from a start to a destination given stations, scheduled departures, and multiple fare/ticket options (including…

Companies: Meta

Last reported Feb 2026

Find All Anagrams in a String

Given strings s and p, return all start indices of substrings in s that are anagrams of p; the core challenge is to detect equal…

Companies: Amazon, Databricks, Microsoft

Hash Table · Sliding Window · String

Last reported Feb 2026

Shuffle an Array

Design a class that stores an integer array and supports reset (returning the original configuration) and shuffle (returning a uniformly random permutation so that all…

Companies: Microsoft, Uber

Array · Design · Math · Randomized

Last reported Feb 2026

Word Count from Remote Document with Large File Handling

Write a program that fetches a document from a URL containing space-separated words and performs word counting. Additionally, explain how you would modify your approach…

Companies: Intuit

Last reported Feb 2026

Count Palindromic Subsequences

Count the number of length-5 palindromic subsequences in a digit string (they must have the form a b c b a) and return the result…

Companies: Meta, Uber

Last reported Feb 2026

Implement Time-Aware GPU Credit Ledger

Companies: OpenAI

Data Structure Design · Heaps & Priority Queues

Last reported Feb 2026

Merge Two Sorted Lists

Companies: Adobe, Google, LinkedIn, Meta +2

Linked List · Recursion

Last reported Feb 2026

Boundary of Binary Tree

Return the boundary of a binary tree: list nodes on the left boundary top-down (excluding leaves), then all leaves left-to-right, then the right boundary bottom-up…

Companies: Amazon, Meta, Snowflake

Binary Tree · Depth-First Search · Tree

Last reported Feb 2026

Product API Integration with Retry Logic

Implement retry logic for a flaky product API and process the JSON response to enable efficient searching of related products.

Companies: Sierra Ai

Last reported Feb 2026

Explain the differences between mutex, semaphore, and spinlock

Compare and contrast the three synchronization primitives (mutex, semaphore, and spinlock) in terms of their implementation, use cases, and performance characteristics.

Companies: NVIDIA

Last reported Feb 2026