LinkedIn interview questions

Nested List Weight Sum II

Given a nested list of integers, where each element is either an integer or a list, compute the sum of all integers weighted by their depth from the bottom up (the deepest level has weight 1).

Medium · Asked 7 times · From LinkedIn | SSE | Phone Screen | Rejected

Find the Celebrity

I encountered the problem Find the Celebrity.

Medium · Asked 5 times · From LinkedIn SDE Interview Experience | Bangalore

Binary Tree Upside Down

Given the 'root' of a binary tree, turn it upside down and return the new root. You can only flip a binary tree if it is a 'left-child only' binary tree or a 'right-child only' binary tree, or a 'balanced' binary tree with at most one child on each side. The…

Medium · Asked 5 times · From LinkedIn Interview Experience

All O(1) Data Structure

Design a data structure that supports increment , decrement , getMaxKey , and getMinKey operations, all in O(1) time.

Hard · Asked 5 times · From LinkedIn | SSE | Systems Infra | Bengaluru | Offer

Max Consecutive Ones III

Given a binary array, find the length of the longest subarray containing only 1s after flipping at most k zeros.

Medium · Asked 4 times · From LinkedIn | Senior Software Engineer | Bangalore | Offer

Shortest Word Distance II

Given a list of words and multiple queries for pairs of words, find the shortest distance (in indices) between the two words for each query.

Medium · Asked 4 times · From SSWE - Phone Screen || LinkedIn

Closest Binary Search Tree Value II

I was asked the LeetCode problem Closest Binary Search Tree Value II.

Hard · Asked 3 times · From LinkedIn | Loop - Second Interview | DSA | Software Engineer | IC2

Max Stack

Implement a MaxStack class which supports push, pop, top, peekMax, and popMax operations.

Hard · Asked 3 times · From LinkedIn | SSE | Infrastructure Team | Rejected

Insert Delete GetRandom O(1) - Duplicates Allowed

Implement the Insert Delete GetRandom O(1) data structure, allowing for duplicate elements.

Hard · Asked 3 times · From Linkedin | SSE | Oct 2025 | Rejected

Maximum Depth of Binary Tree

Given the root of a binary tree, compute the maximum depth (or height) of the tree, which is the number of nodes along the longest path from the root node down to the farthest leaf node.

Easy · Asked 2 times · From LinkedIn Loop Rounds IC2

Max Points on a Line

Given a set of points in a 2D plane, determine the maximum number of points that lie on the same straight line.

Asked 2 times · From LinkedIn Loop Rounds IC2

Find Leaves of Binary Tree

The LeetCode problem Find Leaves of Binary Tree.

Medium · Asked 2 times · From LinkedIn | SSE | Infrastructure Team | Rejected

Number of Islands

A coding problem similar to LeetCode problem 200, Number of Islands . The problem typically involves given an m x n 2D binary grid which represents a map of '1's (land) and '0's (water), and you need to count the number of islands. An island is surrounded by…

Medium · Asked 2 times · From Linkedin - SSE System and Infra Role- First Screening Round experience - waiting for the next update

Nested List Weight Sum

Given a nested list of integers, return the sum of all integers in the list weighted by their depth. Each element is either an integer or a list (whose elements may also be integers or other lists).

Medium · Asked 2 times · From LinkedIn | SSE | Systems Infra | Bengaluru | Offer

K Closest Points to Origin

Given a set of points in 2D space, find the K points closest to the origin (0,0). The problem was extended to finding K nearest neighbors to any arbitrary point in 2D space.

Medium · Asked 2 times · From LinkedIn Senior Software Engineer Interview Experience (Systems Infra team) | Reject

Bulb Switcher (Similar)

A Data Structures & Algorithms question similar to LeetCode's Bulb Switcher problem.

Medium · Asked 2 times · From LinkedIn| Software Engineer

Celebrity Problem

The classic Celebrity Problem.

Medium · Asked 2 times · From LinkedIn [SSE] [Systems Infra] [Ghosted]

Paint House

There are a row of n houses, each can be painted with one of three colors: red, blue or green. The cost of painting each house with a certain color is different. I needed to paint all the houses such that no two adjacent houses have the same color. I had to…

Medium · Asked 2 times · From LinkedIn | On-site | Systems and Infra

Zigzag Level Order Traversal

Given a binary tree, return its node values in a zigzag level order traversal (also known as “snake” order), where the first level is traversed left‑to‑right, the second level right‑to‑left, and so on.

From LinkedIn Loop Rounds IC2

Minimum Length Substring

Find the smallest substring of a given string that satisfies a specific condition (e.g., contains all required characters or meets a particular pattern). The exact requirement was not detailed in the post.

From LinkedIn Loop Rounds IC2

LRU Cache with Counters

Implement an LRU (Least Recently Used) cache that, in addition to standard get/put operations, maintains counters or metrics for cache usage.

From LinkedIn Loop Rounds IC2

Validate Numeric String

Implement a function isNumber(toTest: string): boolean that returns true if the input string represents a valid numeric value and false otherwise. Valid examples: '234' → true, '-455' → true, '23.23' → true. Invalid examples: '1e2' → false, '12^2' → false,…

Easy · From LinkedIn | Phone Screening Round | Software Engineer - Applications

Tournament Tree Problem

The main interview problem was the same as the one discussed in this LinkedIn phone‑screen post: https://leetcode.com/discuss/post/125110/linkedin-phone-screen-tournament-tree-pr-aqv9/. The task involves implementing an optimized solution for a tournament…

From LinkedIn | Phone Screening Round | Software Engineer - Applications

Can Place Flowers Variation with Multiple O(1) Queries

Given a flowerbed represented by an array of 0s (empty) and 1s (occupied), determine if you can place a new flower without violating the no-adjacent-flowers rule. In this variation, you receive multiple queries, each asking whether a flower can be placed at a…

Medium · From LinkedIn | SSE | Phone Screen | Rejected

Shortest Path in a Hidden Grid

Find the shortest path from a start cell to a target cell in a hidden grid where each cell can be either open or blocked. The problem can be solved using Dijkstra's algorithm to explore the reachable cells while minimizing the number of steps.

Medium · From LinkedIn interview experience

Design a Key-Value Store

I was asked to design a Key-Value store. This involved discussing its purpose, storage, compute mechanisms, and sharding strategies.

Hard · Asked 2 times · From LinkedIn Senior Software Engineer Interview Experience (Systems Infra team) | Reject

Design Metrics Aggregation System

Design a system for aggregating metrics.

Hard · Asked 2 times · From Linkedin Staff Infra interview Experience

Design Google Calendar

Design a scalable calendar service like Google Calendar. Discuss architecture, core components, data storage, synchronization, scalability, and design trade‑offs.

From LinkedIn Loop Rounds IC2

Design a Highly Scalable NoSQL Key‑Value Store

Design a system that can store fifty million key‑value pairs and handle one million queries per second, split evenly between reads and writes. The design should address scaling, high throughput, fault tolerance, and low latency.

From LinkedIn interview experience

Implement a Simple Rate Limiter

If you had to implement a simple rate limiter, how would you do it?

From LinkedIn | Senior Software Engineer | Bangalore | Offer

Design Top‑N Leaderboard for Shared Articles

Design a system to maintain a Top‑N leaderboard of the most‑shared articles over rolling windows of 5 minutes, 1 hour, and 24 hours.

From LinkedIn | Senior Software Engineer | Bangalore | Offer

Notification Delivery System Design

Design LinkedIn's notification delivery system. Include requirements such as handling different notification types (connection requests, post likes, job recommendations, InMail), prioritization tiers, delivery channels (push, email, in‑app), scale (~900M…

From LinkedIn Staff Software Engineer — Onsite Experience [April 2026]

Evaluate New PYMK Model with Latency Trade‑off

Hypothetical: You own LinkedIn's "People You May Know" system. The ML team proposes a new recommendation model that improves relevance by 15% but increases latency from 50ms to 200ms. Describe how you would evaluate whether to adopt the new model, including…

From LinkedIn Staff Software Engineer — Onsite Experience [April 2026]

Design Metric Collection and Querying System

The system will both collect metrics from a large fleet of machines, and retrieve them over a requested period of time to be shown in an external visualization system. You can assume that a metric is represented by the [timestamp, node, metric, value] tuple.

From Linkedin Loop || System design round || Software Engineer IC2

Design a Metrics Platform

I was tasked with designing a metrics platform. Key requirements included services publishing metrics, storing, aggregating, and displaying them on a dashboard, and implementing alerting thresholds.

From LinkedIn SDE Interview Experience | Bangalore

Scalable Statistics Collection and Aggregation System Design

We have a big deployment with hundreds of machines each of which is exposing thousands of statistics. You can think that each statistic is represented by the tuple [source, metric-name, value]. We want to be able to collect and aggregate those tuples in a…

Hard · From LinkedIn | SSE | Infrastructure Team | Rejected

Design a Distributed Job Scheduler

Design a distributed job scheduler. Follow up questions were asked as well on the design choices and I was asked if I had to lead the project then how would I go about it.

Hard · From LinkedIn | SSE | Infrastructure Team | Rejected

Design a fast key-value store

Design a fast key-value store with some custome requirements. Focus was more on LLD part than the HLD.

From LinkedIn SWE Infra Interview experience

Second Pass Ranker System Design

Design a "Second Pass Ranker" for the Feed serving billions of users. Constraint: No pre-existing embeddings.

From AI Engineer | LinkedIn | Virtual Onsite | Rejected

System Design: Metrics and Monitoring

I was asked to design a system for collecting, storing, and visualizing metrics, as well as setting up monitoring and alerting. The discussion involved topics such as data ingestion, storage solutions (e.g., time-series databases), aggregation, dashboarding,…

From LinkedIn Interview Experience

System Design: Malicious/Spam URL Detection System

I had to provide a High-Level Design for a system capable of detecting malicious or spam URLs. The discussion also covered the end-to-end execution plan for such a project, from initial design and development to deployment and ongoing maintenance, including…

From LinkedIn Interview Experience

API Design for High Write Traffic

Design an API capable of handling 10,000 queries per second (QPS) for write traffic.

From Linkedin | SSE | Oct 2025 | Rejected

Design a Notification System

Design a scalable notification system. Key requirements include implementing rate limiting for various notification categories (e.g., maximum 5 marketing notifications per user per day) and managing user preferences for different types of notifications.

From Linkedin | SSE | Oct 2025 | Rejected

Design a Lead Routing System

Design a system to route leads to sales representatives efficiently. The system should handle approximately 15,000 leads per day, routing each lead individually to sales people based on criteria such as timezone and region. The product team must be able to…

From Linkedin | SSE | Oct 2025 | Rejected

Design a Metrics Aggregator and Monitoring System

The system design round focused on designing a metrics aggregator and a monitoring system.

Hard · From Linkedin - Senior Software Engineer (System and Infra) - USA - YEO - 5.5 years - Pending review

Data Migration Between Data Centers

Towards the end of the Host Manager round, I was given a system design-like question: 'How to migrate data from one data center to another, with certain conditions applied'.

Hard · From Linkedin - Senior Software Engineer (System and Infra) - USA - YEO - 5.5 years - Pending review

Database Normalization

Explain database normalization concepts, including associated trade-offs like read/write performance and deduplication.

From LinkedIn Interview Experience | IC-2 Infra | Bangalore | Technical Phone Screen

Design Exception Metric Collection and Alarming System

Design an Exception Metric Collection and Alarming System. Handle millions of exceptions per second. Support keyword-based search for exceptions. Provide Top K most frequent and Top K least frequent exception queries. Include an alerting mechanism when…

Hard · From LinkedIn SSE Interview Experience

Design Feature Button Click Counter

Build a system to collect feature button click counts and show aggregated metrics over time for Product Managers.

Medium · From LinkedIn SSE Interview Experience

Design Top N Articles Shared

Design a system to efficiently find the top N most shared articles.

From LinkedIn | SSE | Systems Infra | Bengaluru | Offer

Why LinkedIn?

Why LinkedIn?

Asked 2 times · From LinkedIn SWE Infra Interview experience

Engineering Excellence Definition

What does "engineering excellence" mean to you? How would you define it for a team rather than just for yourself?

From LinkedIn Staff Software Engineer — Onsite Experience [April 2026]

Improving Quality of an Inherited System

Describe a system you inherited that had quality issues. How did you approach improving its quality?

From LinkedIn Staff Software Engineer — Onsite Experience [April 2026]

Why are you leaving my current company?

Why are you leaving my current company?

From LinkedIn SWE Infra Interview experience

On-call in current team

What does on-call look like in my current team?

From LinkedIn SWE Infra Interview experience

Mentoring Experience

Discuss your experience with mentoring others.

From Linkedin | SSE | Oct 2025 | Rejected

Reason for Previous Job Change

Discuss the reasons for your previous job change.

From Linkedin | SSE | Oct 2025 | Rejected

Differences Between Companies

Describe the observed differences upon joining your current company compared to your previous one.

From Linkedin | SSE | Oct 2025 | Rejected

Experience with Operations/On-Call Work

Discuss any experience you have with operations work, on-call duties, or similar responsibilities.

From Linkedin | SSE | Oct 2025 | Rejected

Conflict with Management

Describe a conflict you faced with management and how you handled the situation.

From Linkedin | SSE | Oct 2025 | Rejected

Staying Current with Tech During Career Break

Explain how you have kept up with advancements in the tech industry during a career break.

From Linkedin | SSE | Oct 2025 | Rejected

Interesting Tech Article/Topic

Share one interesting thing you have recently read about in the tech industry. I specifically mentioned Discord's approach to indexing trillions of messages.

From Linkedin | SSE | Oct 2025 | Rejected

Technical Growth Over Past Year

Describe your technical growth and development over the past year.

From Linkedin | SSE | Oct 2025 | Rejected

Explain a Project and Discuss Trade-offs

I was asked to explain a project I had worked on, including details, follow-up questions, and discussions around trade-offs.

From LinkedIn| Software Engineer

Conflicting situations faced in any critical project

Conflicting situations faced in any critical project.

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Impactful project from which I was able to move out to other project with minimal disruption

Impactful project from which I was able to move out to other project with minimal disruption.

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Define a Quality Product/System

How do you define a quality product/system?

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Code Review Strategy

Describe your strategy regarding code reviews.

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Managing Projects with Junior Engineers

Talk about a project that had many junior engineers and how I kept the project quality high/ If your team keeps growing and you get more junior engineers, what do you do?

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Improving a Legacy Application as Staff SWE

As a hypothetical situation, Imagine you join LinkedIn on a massive team that owns a legacy application. The application lacks adequate testing and monitoring and has slow response times. Consumers complain about this. Deployment of the application often…

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Prioritizing Issues and Microservices Migration

Rank the following in terms of priority: bugs, no testing, no monitoring, slowness. What do you tackle first? How do you eventually turn this into micro services?

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Determining Success of a Service

What do you look for when determining the success of a service?

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Principles of Mentorship

What are your principles of mentorship? How do you manage technical and non-technical mentorship?

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Helping Engineers Grow

Talk about a time where you helped grow engineers.

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

Discuss a Complex, Large-Scale Project Led

Talk in detail about the most complex and challenging project I led in the recent times which had a very large scale. I framed my answer step-by-step as follows (along with few follow-ups from the HM): Team and My role, Customer Problem & Business impact, Key…

From LinkedIn | Staff Software Engineer | Interview Experience | June 2025 | Offer

LP Questions

From Staff Software Engineer Screening

Cache Hit/Miss Ratio Calculation

Given different workload patterns, calculate or predict the cache hit and miss ratios, discussing how workload characteristics affect cache performance.

From LinkedIn Loop Rounds IC2

Java Internals Discussion

Discussion on Java internals including multi-threading concepts (Callable/Runnable), HashMap internals, Concurrent HashMap, and JVM.

From Linkedin SSE Interview

Garbage Collector Internals

How does Garbage Collector work? How does a Garbage Collector know which object to delete? Identify a case where the object has no references, but still the Garbage Collector does not delete the object

From LinkedIn | SSE | Infrastructure Team | Rejected

ACID Properties of Database

ACID properties of Database

From LinkedIn | SSE | Infrastructure Team | Rejected

Transformation and Sorting Problem

The first problem required explaining and solving a mathematical transformation followed by sorting. The second problem was about rejection sampling, similar to the rand7() → rand10() problem.

Medium · From Linkedin | Software Engineer, Machine Learning Interview Experience

Two-Pointer Implementation Problem

This problem involved using a two-pointer technique to solve a specific array manipulation task.

Medium · From Linkedin | Software Engineer, Machine Learning Interview Experience

Rejection Sampling Problem

The problem required generating a random number between 1-10 using a function that generates numbers between 1-7, similar to the rand7() → rand10() problem.

Medium · From Linkedin | Software Engineer, Machine Learning Interview Experience

Partition Array into K Subsets with Equal Sum

The problem required partitioning an array into K subsets with equal sum, which is a classic backtracking problem.

Hard · From Linkedin | Software Engineer, Machine Learning Interview Experience

Cold-Start Recommender System

The system design problem focused on creating a cold-start recommender system, discussing data preparation, feature engineering, handling sparse/implicit data, model training, and candidate generation.

Hard · From Linkedin | Software Engineer, Machine Learning Interview Experience

Recommendation and Ranking System

This system design problem involved designing a recommendation and ranking system, covering aspects like data pipelines, feature engineering, and model deployment.

Hard · From Linkedin | Software Engineer, Machine Learning Interview Experience

Discuss System Issues

Discuss any issues encountered in a previous system, focusing on performance, poor code, or similar aspects.

From Linkedin | SSE | Oct 2025 | Rejected

Software Design Patterns

Explain what software design patterns are and why they are important.

From Linkedin | SSE | Oct 2025 | Rejected

CAP Theorem

Explain the CAP theorem.

From Linkedin | SSE | Oct 2025 | Rejected

Concurrency vs. Parallelism

Explain the difference between concurrency and parallelism.

From Linkedin | SSE | Oct 2025 | Rejected

Multithreading Code Output

Determine the output of a given multithreading code snippet.

From Linkedin | SSE | Oct 2025 | Rejected

Measuring Project Performance and Success

Discuss how project performance and success were measured. This includes details on performance testing methodologies and specific metrics observed, such as p90 latency.

From Linkedin | SSE | Oct 2025 | Rejected

Number of Islands and OS Basics

The technical screening round started with a coding question similar to 'Number of Islands'. Following this, there was a 30-minute discussion on past projects and fundamental OS concepts including processes, threads, semaphores, mutexes, PCB, TCB, heap,…

From Linkedin - Senior Software Engineer (System and Infra) - USA - YEO - 5.5 years - Pending review

Process vs. Thread

Differentiate between a process and a thread.

From LinkedIn Interview Experience | IC-2 Infra | Bangalore | Technical Phone Screen

Kafka Real-World Scenario

I was presented with a real-world scenario question related to Kafka and its applications/issues.

From LinkedIn Sr SWE - Systems and Infra | Phone Screen + Onsite | US | Reject

Strategic Problem Approach

The Hiring Manager presented a problem and asked how I would approach it, including which teams I would reach out to, how to structure approaches, and conducting PoCs, emphasizing that I didn't have to solve everything alone.

From LinkedIn| Software Engineer

HTTP Methods Discussion

Discuss Theory Question Like HTTP Methods POST, GET, PUT and Delete WHy cannot we use POST to fetch data and GET to send data, what happens?

From IC3 FullStack Engineer - Frontend Heavy @ Linkedln

Accessibility Discussion

Discuss Accessibility.

From IC3 FullStack Engineer - Frontend Heavy @ Linkedln

SQL Question on Window Functions and Rank

During my telephonic screening, I was asked a medium-difficulty SQL question that required the use of window functions and ranking. There were also several follow-up questions.

Medium · From LinkedIn Senior Data Engineer (IC3) On Site

Operating Systems Concepts

Explain the differences between processes and threads. Discuss mutexes versus semaphores. What are deadlocks and how can they be prevented or handled? Explain paging and page faults in memory management.

From Linkedin | Senior Software Engineer Systems Infrastructure | Sunnyvale | Phone Screen