Interview questions

Swap values to equalize array sums

Given two integer arrays of potentially different lengths, find all pairs (a, b) where a belongs to the first array and b belongs to the…

Companies: eBay

Last reported Jul 2026

Delete and Earn

Aggregate points for each distinct number (value * frequency), then choose a subset of values maximizing sum with the constraint that taking value x forbids…

Companies: Walmart, Walmart Labs

Array · Dynamic Programming · Hash Table

Last reported Jul 2026

Find Distance in a Binary Tree

Given a binary tree and two node values, compute the distance (number of edges) between the corresponding nodes. Key approaches include finding their lowest common…

Companies: Amazon

Last reported Jul 2026

My Calendar III

Online interval insertions where after each [start, end) booking you must report the current maximum number of simultaneously overlapping events (the largest k such that…

Companies: Datology

Last reported Jul 2026

Web Crawler Multithreaded

Create a web crawler that starts from a given URL and crawls all reachable URLs within the same domain using breadth-first search traversal. Implement multithreading…

Companies: Anthropic, Monzo, OpenAI, Opendoor +1

Last reported Jul 2026

File Path Search

Given a list of absolute file paths, implement a search function that accepts a search string representing either a directory or file name. The function…

Companies: Apple

Last reported Jul 2026

Largest Subarray Length K

Given an array and integer k, find the contiguous subarray of length k that maximizes a specified metric (commonly the sum); this is an easy…

Companies: Oracle

Last reported Jul 2026

Number of Students Unable to Eat Lunch

Given a queue of students with binary sandwich preferences and a stack of sandwiches (top first), students rotate to the back until someone takes the…

Companies: Salesforce

Last reported Jul 2026

Valid Parenthesis String

Determine whether a string containing '(', ')', and '*' (where '*' can represent '(', ')', or empty) can be assigned so the parentheses are balanced…

Companies: Apple, Microsoft, Oracle

Bracket Sequences · Dynamic Programming · Greedy · Stack

Last reported Jul 2026

Implement CRUD REST APIs

Design and implement basic CRUD (Create, Read, Update, Delete) operations for a REST API system. Include appropriate HTTP methods, request/response handling, and data…

Companies: Disney, DoorDash, Netflix, Speak +2

Last reported Jul 2026

Find Most-Viewed Product by Date

Given an array of e-commerce activity tuples containing user_id, product_id, event_time, and event_type, write a function that returns the product_id with the highest number of…

Companies: Intuit

Last reported Jul 2026

Invert Binary Tree

Given the root of a binary tree, invert it by producing its mirror image—swap the left and right child of every node—and return the root…

Companies: Target

Last reported Jul 2026

Maximum Number of Events That Can Be Attended

Given up to 1e5 intervals [start,end] where you can attend an event on any integer day within its range but only one event per day…

Companies: Oracle

Last reported Jul 2026

Reverse Substrings Between Each Pair of Parentheses

Given a balanced string of lowercase letters and parentheses, reverse the substrings inside each matched pair from the innermost outward and return the resulting string…

Companies: Oracle

Last reported Jul 2026

Valid Perfect Square

Determine whether a positive integer is a perfect square without using built-in sqrt — i.e., decide if there exists an integer x such that x*x…

Companies: LinkedIn

Last reported Jul 2026

Meeting Scheduler

Given two people's lists of available time intervals and a required meeting duration, find the earliest time interval where both are free for at least…

Companies: Coupang, Microsoft, Uber

Last reported Jul 2026

Fibonacci Number

Compute F(n) defined by F(0)=0, F(1)=1 and F(n)=F(n-1)+F(n-2); return the nth Fibonacci number for 0 ≤ n ≤ 30. The task tests handling a simple…

Companies: Bloomberg

Last reported Jul 2026

Find the Closest Element to a Target in an Array

Given an integer array and a target value, find the element in the array that is closest to the target (minimum absolute difference). If two…

Companies: Walmart

Last reported Jul 2026

Longest Well-Performing Interval

Convert days to +1 (hours>8) and -1 (hours<=8) and find the longest contiguous subarray whose sum is >0. This reduces to finding the farthest pair…

Companies: Chewy

Last reported Jul 2026

Range Assignment Queries: Replace Array Subranges with a Given Value

Given an array and a list of queries, each represented as a tuple (L, R, K), return the final state of the array after applying…

Companies: Google

Last reported Jul 2026

Subarray Sum Equals K (Return the Subarray)

Given an array of integers and a target value K, find a contiguous subarray whose elements sum to K and return the subarray elements in…

Companies: Atlassian, Walmart

Last reported Jul 2026

Build an In-Memory Workflow Engine with Dependency Ordering and Concurrent Execution

Build a generic in-memory workflow engine that registers named steps with dependencies, validates the graph for missing steps and cycles, and executes steps in correct…

Companies: Reap

Last reported Jul 2026