Interview questions

Union / Merge of Two Sorted Interval Lists

Given two sorted lists of non-overlapping intervals (A and B), return a new sorted list representing the union of both interval lists. Any overlapping or…

Companies: Meta

Last reported Apr 2026

Asteroid Collision

Given signed integers for asteroid sizes and directions, determine which asteroids remain after sequential collisions where only opposite-moving neighbors (positive then…

Companies: Amazon, D. E. Shaw, JPMorgan Chase, Meta +2

Array · Simulation · Stack

Last reported Mar 2026

Convert Sampled Call Stacks into Start and End Events

Convert a sequence of sampled call stacks into function entry and exit events. Handle recursive calls and discuss the effect of limited history.

Companies: Anthropic

Arrays & Strings · Profiling · Recursion · Stacks

Last reported Mar 2026

Merge Sorted Arrays

Given two sorted arrays, merge them into a single sorted array without using built-in sort functions. The resulting array should contain all elements from both…

Companies: Meta

Last reported Mar 2026

Process Orders with Partial Fulfillment

Given a priority queue of orders, each with a name, amount, and type (Fizz or Buzz), match Fizz orders to Buzz orders and fulfill them…

Companies: Google

Last reported Mar 2026

Usage-Based Billing Calculator

Design a system to calculate the total cost of resource usage across a list of time intervals, given a default price per unit time and…

Companies: Crusoe

Last reported Mar 2026

Binary Tree Vertical Order Traversal

Group tree nodes by their horizontal (column) index and return a list of columns from leftmost to rightmost, preserving top-to-bottom order and left-to-right ordering for…

Companies: Bloomberg, Meta, Uber

Last reported Mar 2026

Maximum Sum of Non-Adjacent Elements

Given an array of integers, select two elements at non-adjacent indices such that their sum is maximized. Return the maximum possible sum.

Companies: Meta

Last reported Mar 2026

Moving Average from Data Stream

Design a data structure that, given a continuous stream of numbers and a fixed window size k, returns the moving average of the last k…

Companies: Box, Google, Meta, Spotify

Array · Data Stream · Design · Queue

Last reported Mar 2026

Priority Queue Implementation

Implement a priority queue data structure from scratch without using built-in priority queue libraries. Your implementation should support core operations such as insert…

Companies: Microsoft

Last reported Mar 2026

Making A Large Island

Given an n×n binary grid where you can flip at most one 0 to 1, compute the largest possible 4-directional island size after the flip…

Companies: DoorDash, Meta, TikTok, Uber

Array · Breadth-First Search · Depth-First Search · Matrix

Last reported Mar 2026

Car Pooling

Given trips as [numPassengers, from, to] on a one-way (eastbound) route, determine if the vehicle's passenger count ever exceeds capacity while picking up and dropping…

Companies: Meta

Last reported Mar 2026

Merge Three Sorted Arrays

Design an algorithm to merge three sorted arrays into a single sorted array. This is similar to the LeetCode question 'Merge Sorted Arrays' but involves…

Companies: Meta

Last reported Mar 2026

Serialize and Deserialize N-ary Tree

Design algorithms to serialize an N-ary tree into a single string and deserialize it back, preserving node values and the arbitrary number and order of…

Companies: Apple, Bloomberg, Rubrik, TikTok

Breadth-First Search · Depth-First Search · String · Tree

Last reported Mar 2026

Zigzag Conversion

Arrange the characters of a string into a zigzag pattern across numRows and then read the rows sequentially to produce the converted string. The core…

Companies: Amazon, Bloomberg, Google, Oracle +1

String

Last reported Mar 2026

Encode and Decode Strings

Design a pair of functions to serialize a list of strings into a single string and deserialize it back losslessly, handling arbitrary characters and empty…

Companies: OpenAI

Last reported Mar 2026

Longest Uncommon Subsequence II

Find the length of the longest string in the array that is a subsequence of itself but not a subsequence of any other string in…

Companies: Netflix

Last reported Mar 2026

Maximum Vacation Days

Given a flights graph and a matrix of vacation days per city per week, start at city 0 and choose each week whether to stay…

Companies: Apple, Datadog, Meta

Last reported Mar 2026

Calculate Total Shipping Cost for an Order

Given an order containing items and quantities, and a shipping cost structure, implement a function to calculate the total shipping cost. The shipping cost structure…

Companies: Stripe

Last reported Mar 2026

Find Minimum in Rotated Sorted Array

Given an ascending array of unique integers that has been rotated, find its minimum element in O(log n) time by identifying the rotation pivot using…

Companies: Meta

Last reported Mar 2026

Range Sum of BST

Given the root of a binary search tree and an inclusive range [low, high], return the sum of all node values that fall within the…

Companies: Meta

Last reported Mar 2026

Subarray Sum Equals K

Count the number of contiguous, non-empty subarrays whose elements sum to k. Because nums can include negatives (so two-pointer sliding window doesn't work), use cumulative…

Companies: Amazon, Apple, Bloomberg, Google +3

Array · Hash Table · Prefix Sum

Last reported Mar 2026