Interview questions

Cheapest Flights Within K Stops

Find the minimum-cost route from src to dst in a directed weighted graph with the constraint of at most k stops (i.e., a bound on…

Companies: Flipkart, Illumio, Meta, Oracle +1

Breadth-First Search · Depth-First Search · Dynamic Programming · Graph Theory

Last reported Oct 2026

Top K Frequent Elements

Given an integer array and k, return the k most frequent elements — the core challenge is to count element frequencies and extract the top-k…

Companies: Amazon, Bloomberg, Google, Meta +9

Array · Bucket Sort · Counting · Divide and Conquer

Last reported Oct 2026

Maximum Number of Points From Grid Queries

For each query threshold, compute how many distinct cells you can reach from the top-left by moving 4-directionally through cells whose value is strictly less…

Companies: Uber

Array · Breadth-First Search · Heap (Priority Queue) · Matrix

Last reported Sep 2026

Kth Largest Element in an Array

Return the k-th largest element (by sorted order, not distinct) from an unsorted array. For inputs up to ~1e5 elements, solve it faster than full…

Companies: Bloomberg, LinkedIn, Meta, Salesforce +1

Array · Divide and Conquer · Heap (Priority Queue) · Quickselect

Last reported Sep 2026

Task Scheduler

Given tasks labeled A–Z and a cooldown n, compute the minimum number of CPU intervals (including idles) to finish all tasks so that identical tasks…

Companies: Amazon, Apple, Databricks, Docker +3

Array · Counting · Greedy · Hash Table

Last reported Sep 2026

Closest Binary Search Tree Value II

Given a BST, a real-valued target and an integer k, return the k node values in the tree closest to the target. The challenge is…

Companies: Amazon, LinkedIn

Binary Search Tree · Binary Tree · Depth-First Search · Heap (Priority Queue)

Last reported Sep 2026

Furthest Building You Can Reach

Given an array of building heights and limited bricks and ladders, find the furthest building index you can reach from 0 by covering each positive…

Companies: D. E. Shaw, SchröDinger

Array · Greedy · Heap (Priority Queue)

Last reported Aug 2026

Merge k Sorted Lists

Companies: Amazon, Meta, NVIDIA, Oracle +3

Divide and Conquer · Heap (Priority Queue) · Linked List · Merge Sort

Last reported Aug 2026

Number of Orders in the Backlog

Simulate batched buy/sell order matching where each buy matches with the lowest-price sell (and each sell with the highest-price buy), allowing partial fills until no…

Companies: Amazon, Citadel

Array · Heap (Priority Queue) · Simulation

Last reported Aug 2026

K Closest Points to Origin

Given N points on the plane and an integer k, return the k points with the smallest Euclidean distance to the origin (order doesn't matter)…

Companies: Airbnb, Amazon, Asana, Meta

Array · Divide and Conquer · Geometry · Heap (Priority Queue)

Last reported Aug 2026

Find Median from Data Stream

Maintain a data structure that supports adding integers from a stream and returning the current median efficiently for many interleaved addNum and findMedian calls. The…

Companies: Adobe, Amazon, D. E. Shaw, Intuit +4

Data Stream · Design · Heap (Priority Queue) · Sorting

Last reported Aug 2026

Two Best Non-Overlapping Events

Given a set of weighted intervals, pick at most two non-overlapping events (events are inclusive, so the next must start at least end+1) to maximize…

Companies: Goldman Sachs, Grammarly

Array · Binary Search · Dynamic Programming · Heap (Priority Queue)

Last reported Jul 2026

Find K Pairs with Smallest Sums

Given two non-decreasing arrays, return the k pairs (one element from each) with the smallest sums — the challenge is to efficiently produce the smallest…

Companies: LinkedIn

Array · Heap (Priority Queue)

Last reported Jul 2026

Meeting Rooms III

Assign each meeting (with unique start times) to the lowest-numbered available room or delay it (keeping its duration and prioritizing earlier original start times) until…

Companies: Apple, Docusign, Google, Meta +2

Array · Hash Table · Heap (Priority Queue) · Simulation

Last reported Jul 2026

Sliding Window Maximum

Given an integer array and a window size k, return the maximum value for each contiguous subarray (sliding window) as it moves one step to…

Companies: Amazon, Bloomberg, D. E. Shaw, Expedia +7

Array · Heap (Priority Queue) · Monotonic Queue · Queue

Last reported Jun 2026

Design Search Autocomplete System

Design an online autocomplete system that processes characters one-by-one, returning the top 3 historically most frequent sentences that match the current prefix (ranked by…

Companies: Google, Netflix, Pinterest, Vercel

Data Stream · Depth-First Search · Design · Heap (Priority Queue)

Last reported May 2026

Network Delay Time

Given a directed, nonnegative-weighted graph and a start node k, compute single-source shortest-path distances and return the maximum distance (the time for the signal to…

Companies: CrowdStrike, NVIDIA

Breadth-First Search · Depth-First Search · Dijkstra's Algorithm · Graph Theory

Last reported Apr 2026

Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit

Find the length of the longest contiguous subarray whose maximum minus minimum is ≤ limit; the key challenge is maintaining the window's current min and…

Companies: MongoDB, Uber

Array · Heap (Priority Queue) · Monotonic Queue · Ordered Set

Last reported Apr 2026

Single-Threaded CPU

Given tasks with enqueue and processing times, return the order a single-threaded CPU will process them when it always picks the available task with the…

Companies: DoorDash, TikTok

Array · Heap (Priority Queue) · Sorting

Last reported Oct 2025

Find the Safest Path in a Grid

Compute each cell's Manhattan distance to the nearest thief, then find a path from (0,0) to (n-1,n-1) that maximizes the minimum of those distances along…

Companies: Google, Meta, Uber

Array · Binary Search · Breadth-First Search · Heap (Priority Queue)

Last reported May 2025

Reorganize String

Rearrange the characters of a string so that no two adjacent characters are the same, returning any valid permutation or "" if none exists. Key…

Companies: Amazon, D. E. Shaw, Tesla

Counting · Greedy · Hash Table · Heap (Priority Queue)

Last reported Jan 2025

Shortest Subarray with Sum at Least K

Find the length of the shortest contiguous subarray whose sum is at least k, or return -1 if none exists. Because nums can contain negative…

Companies: Meta

Array · Binary Search · Heap (Priority Queue) · Monotonic Queue

Last reported Jan 2025