Interview questions

Find the Length of the Longest Common Prefix

Given two arrays of positive integers, return the maximum length (in digits) of a common leftmost-digit prefix shared by any number from arr1 and any…

Companies: Apple

Last reported Jun 2026

In-Memory Database: Implement SQL-Like Operations

Build an in-memory database that supports basic SQL-like operations including insert, query with WHERE clauses, and ORDER BY functionality. Implement efficient data storage…

Companies: Anthropic, OpenAI, Two Sigma

Last reported Jun 2026

Random Pick with Weight

Given an array of positive weights, implement pickIndex() to return index i with probability w[i]/sum(w); the typical approach preprocessing prefix sums and using a random…

Companies: Amazon, Apple, Goldman Sachs, Meta +4

Array · Binary Search · Math · Prefix Sum

Last reported Jun 2026

Find the Longest Substring Containing Vowels in Even Counts

Find the length of the longest substring where each vowel (a, e, i, o, u) occurs an even number of times. This is typically solved…

Companies: Amazon, Meta

Last reported Jun 2026

Aggregate Recent Message Events And Active Chats

Companies: OpenAI

Data Structure Design

Last reported Jun 2026

Implement A Contiguous Memory Allocator With Free-Block Coalescing

Companies: OpenAI

Data Structure Design · Memory Management

Last reported Jun 2026

Closest Binary Search Tree Value

Given a Binary Search Tree and a target numeric value, return the value of the node in the tree that is closest to the target…

Companies: Expedia, Meta, Roblox

Binary Search · Binary Search Tree · Binary Tree · Depth-First Search

Last reported Jun 2026

Combination Sum

Given distinct candidate integers and a target, return all unique order-insensitive combinations where each candidate may be used unlimited times and the numbers sum to…

Companies: Expedia

Last reported Jun 2026

Gas Station

Given two arrays gas and cost around a circular route, find the unique starting station index from which you can travel clockwise once without your…

Companies: Adobe, Bloomberg, Expedia, Goldman Sachs +2

Array · Greedy

Last reported Jun 2026

Minimum Number of Days to Make m Bouquets

Find the minimum day such that you can form at least m bouquets, each requiring k adjacent flowers that have bloomed (return -1 if impossible…

Companies: Amazon, Apple, Flipkart, Meta

Array · Binary Search

Last reported Jun 2026

Maximize Profit from Task Assignment

Given arrays of task difficulties and corresponding profits plus worker abilities, assign at most one task to each worker (a worker can do any task…

Companies: Amazon

Last reported Jun 2026

Search a 2D Matrix

Given an m×n matrix where each row is sorted and the first element of each row is greater than the last of the previous row…

Companies: Amazon, Goldman Sachs, Meta, Microsoft +1

Array · Binary Search · Matrix

Last reported Jun 2026

Search in a Sorted Array of Unknown Size

Given a sorted ascending array with unknown length accessible only via a bounded reader (out‑of‑range returns a sentinel), find the index of a target or…

Companies: Amazon

Last reported Jun 2026

Streaming Entropy with Numerical Stability

Companies: OpenAI

Last reported Jun 2026

Unique Binary Search Trees

Count the number of structurally unique binary search trees that can be formed using values 1..n. This is equivalent to computing the nth Catalan number…

Companies: Amazon

Last reported Jun 2026

Find All Combinations of Bag Sizes That Sum to a Target Capacity

Given a list of chocolate bag sizes (each size may be used any number of times) and a target capacity n, find all unique combinations…

Companies: Apple

Last reported Jun 2026

Jump Game

Given an array where each value is the maximum jump length from that index, determine whether you can reach the last index starting from the…

Companies: Amazon, Meta, Microsoft

Array · Dynamic Programming · Greedy

Last reported Jun 2026

Pizza Toppings Cost Analysis

Given base pizza prices and topping prices, determine which total price closest to a target budget can be achieved by choosing one base and any…

Companies: Amazon

Last reported Jun 2026

dive deep to your project and ask questions around it, leetcode mediuem level coding

Companies: TikTok

Last reported Jun 2026

First Unique Number

Design a data structure that, given an initial list and a stream of added numbers, returns the first integer that appears exactly once at any…

Companies: Uber

Array · Data Stream · Design · Hash Table

Last reported Jun 2026

Flatten Nested Tree Iterator

Given a nested tree hierarchy (e.g., categories and subcategories), implement an iterator class with a next() method that traverses and returns each node's value in…

Companies: Adobe

Last reported Jun 2026

Leetcode Hard question: Sliding Window Maximum

Companies: Microsoft

Last reported Jun 2026