Lg Ad Solutions · Software Engineer
Updated · 2026-10-02

Lg Ad Solutions Software Engineer
Interview Guide

THE 60-SECOND BRIEF

A Software Engineer at Lg Ad Solutions plays a pivotal role in shaping the future of Connected TV (CTV) and cross-screen advertising. Operating at the intersection of high-performance computing, massive data scale, and real-time decision-making, engineers here build the systems that power intelligent ad delivery to millions of screens globally. The work directly impacts how brands engage with audiences, making algorithmic efficiency, low-latency execution, and system reliability central to every engineering endeavor. The engineering team at Lg Ad Solutions tackles complex challenges, such as processing billions of ad requests daily, managing high-throughput data pipelines, and maintaining robust cloud infrastructure.

This guide is scoped to a Software Engineer candidate at Lg Ad Solutions.

Lg Ad Solutions candidates report 3 rounds over 3-5 weeks. The stages below are what candidates describe, not a published process.

System DesignAlgorithmsC++

23 min read

Browse Software Engineer questions

See the practice prompts

20Practice promptsAcross five skill areas

A Software Engineer at Lg Ad Solutions plays a pivotal role in shaping the future of Connected TV (CTV) and cross-screen advertising. Operating at the intersection of high-performance computing, massive data scale, and real-time decision-making, engineers here build the systems that power intelligent ad delivery to millions of screens globally. The work directly impacts how brands engage with audiences, making algorithmic efficiency, low-latency execution, and system reliability central to every engineering endeavor. The engineering team at Lg Ad Solutions tackles complex challenges, such as processing billions of ad requests daily, managing high-throughput data pipelines, and maintaining robust cloud infrastructure. Whether you are optimizing a backend service in C++ or Golang, developing intuitive fullstack interfaces, or scaling cloud-native infrastructure, your contributions will directly influence the company’s core ad-serving engine and analytics platforms. To succeed in this role, you must possess a passion for solving open-ended problems and a drive to build highly scalable systems. The engineering culture is deeply collaborative, requiring close alignment with product managers, data scientists, and infrastructure specialists. If you thrive in environments where sub-millisecond latency is the standard and system design is treated as an art form, this position offers an exceptionally rewarding technical playground.

01

Technical Recruiter Screen

reported

Initial screening to assess candidate's fit and technical background.

What to demonstrate

  • Initial screening to assess candidate's fit and technical background
  • Depth in System Design

How to prepare

  • Be able to walk your CV end to end in two minutes, and say why this company specifically.
  • Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Lg Ad Solutions Software Engineer candidate reports ↗
02

Deep-Dive Technical Evaluations

reported

In-depth technical assessments focusing on practical problem-solving and real-world scenarios.

What to demonstrate

  • In-depth technical assessments focusing on practical problem-solving and real-world scenarios
  • Depth in System Design

How to prepare

  • Answer aloud and timed: Given an array of integers, find the contiguous subarray with the largest sum and write an optimal solution.
  • Answer aloud and timed: Implement an efficient algorithm to detect a cycle in a directed graph.
Lg Ad Solutions Software Engineer candidate reports ↗
03

Leadership and Behavioral Assessment

reported

Evaluation of candidate's collaborative potential and alignment with company values.

What to demonstrate

  • Evaluation of candidate's collaborative potential and alignment with company values
  • Depth in System Design

How to prepare

  • Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
  • Re-read the description of the leadership and behavioral assessment above and write down what you would ask to confirm before it.
Lg Ad Solutions Software Engineer candidate reports ↗

PracHub editorial advice for the preparation topics above.

01

Focus on Resource Efficiency

In the ad-tech space, CPU cycles and network bandwidth translate directly to operational costs. When writing code or designing systems, always explain how your choices minimize memory usage, network overhead, and database roundtrips.

02

Do not jump straight into writing code during your technical rounds

Spending the first 5 minutes clarifying the requirements, confirming inputs/outputs, and discussing your high-level strategy will prevent you from wasting time on the wrong solution.

03

Be Precise with Big-O Notation

When analyzing your code, go beyond simply stating the time complexity. Explain the space complexity of your approach, including the overhead of recursive call stacks or auxiliary data structures, and discuss how the algorithm behaves with extremely large datasets.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

17 technical prompts0 include a worked solution

Explain the mechanics of Merge Sort and discuss its time and space complexity compared to other sorting algori

medium
Algorithms & Data Structures

Explain the mechanics of Merge Sort and discuss its time and space complexity compared to other sorting algorithms.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Walk through the process of reversing a singly linked list both iteratively and recursively.

medium
Algorithms & Data Structures

Walk through the process of reversing a singly linked list both iteratively and recursively.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Given an array of integers, find the contiguous subarray with the largest sum and write an optimal solution.

medium
Algorithms & Data Structures

Given an array of integers, find the contiguous subarray with the largest sum and write an optimal solution.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Implement an efficient algorithm to detect a cycle in a directed graph.

medium
Algorithms & Data Structures

Implement an efficient algorithm to detect a cycle in a directed graph.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Write a function to find the lowest common ancestor of two nodes in a binary tree.

medium
Algorithms & Data Structures

Write a function to find the lowest common ancestor of two nodes in a binary tree.

Approach
  1. Restate the input: its shape, its size, and what is guaranteed about it.
  2. Name the brute-force solution and its complexity before improving on it.
  3. Choose the data structure from the access pattern, not from familiarity.
  4. State the target complexity and say which constraint rules the naive version out.
Follow-up
  • How does this change if the input no longer fits in memory?
  • What is the worst case, and how likely is it on real data?

Built from the rounds and topics Lg Ad Solutions candidates report.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Map the Lg Ad Solutions loop
  • Write out the reported sequence: Technical Recruiter Screen, Deep-Dive Technical Evaluations, Leadership and Behavioral Assessment.
  • For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.

Deliverable: A one-page map of the 3 reported rounds, with the weakest marked.

02Work System Design
  • Spend the session on System Design, which Lg Ad Solutions candidates report being tested on.
  • Write one worked example in System Design and time yourself on it.

Deliverable: One timed worked example in System Design.

03Work Algorithms
  • Spend the session on Algorithms, which Lg Ad Solutions candidates report being tested on.
  • Write one worked example in Algorithms and time yourself on it.

Deliverable: One timed worked example in Algorithms.

04Work C++
  • Spend the session on C++, which Lg Ad Solutions candidates report being tested on.
  • Write one worked example in C++ and time yourself on it.

Deliverable: One timed worked example in C++.

05Answer out loud: Algorithms & Data Structures
  • Answer aloud, timed: Explain the mechanics of Merge Sort and discuss its time and space complexity compared to other sorting algorithms.
  • Answer aloud, timed: Walk through the process of reversing a singly linked list both iteratively and recursively.

Deliverable: Spoken answers to 2 reported Algorithms & Data Structures question(s), under time.

06Answer out loud: System Design & Architecture
  • Answer aloud, timed: Design a high-throughput, low-latency rate limiter for an external API gateway.
  • Answer aloud, timed: How would you architect a distributed message queue capable of handling millions of events per second with guaranteed delivery?

Deliverable: Spoken answers to 2 reported System Design & Architecture question(s), under time.

07Answer out loud: Platform & Infrastructure
  • Answer aloud, timed: How do you manage infrastructure as code (IaC) across multiple cloud environments to prevent configuration drift?
  • Answer aloud, timed: Describe your approach to diagnosing a sudden latency spike in a microservices architecture running on Kubernetes.

Deliverable: Spoken answers to 2 reported Platform & Infrastructure question(s), under time.

Expand any day for tasks and deliverables. Your progress is saved on this device.

Behavioural rounds judge the decision you made and what it cost.

Reverse your own decision and price the reversal

medium
reversibilitymeasurementmigrations

Describe a technical decision you made and later reversed. Pick one that cost something: a service you split and merged back, a cache you added and removed, an index you created that pushed the planner onto a worse plan, a projection you rebuilt from scratch. State what you believed when you decided, the measurement that changed your mind, how long the wrong version ran in production, and what the reversal cost in migrations, dual writes, and a deprecation window for callers you did not own.

Approach
  1. State the original rationale without irony, in the version you would still defend given what was known then. If it is not defensible, the story is about carelessness rather than judgement, and a different example serves you better.
  2. Give the measurement that moved with a before and after: the p99 that did not improve, the cache hit rate that sat at 40%, the plan that flipped to a sequential scan once the table passed a size you can name.
  3. Cost the reversal in steps, not adjectives: expand-and-contract deploys, the dual-write window, the callers who had to be notified, the rows already written in the wrong shape that had to be backfilled or abandoned.
  4. Distinguish reversal from rewrite by naming what you kept. Most good reversals preserve the schema or the interface and undo one decision inside it, which is also why they were affordable.
Follow-up
  • What in that decision was irreversible, and did you know it was irreversible when you made it?
  • How did you tell the people who had already built on top of the original decision?

Narrate an outage you owned from page to postmortem

hard
incident responseblast radiuspostmortems

Pick an incident you personally drove, ideally one where writes were affected rather than reads. In six to eight minutes: state the symptom as it first appeared on a dashboard, the blast radius you established before you knew the cause, the mitigation you applied and when, the mechanism you eventually proved, and the follow-up that would prevent a repeat. Bring numbers: error rate, tenants affected, minutes to mitigate, minutes to resolve. If you cannot name what you measured, choose a different incident.

Approach
  1. Open on the signal rather than the cause: which metric at which percentile moved, on which service, at what time, so the listener follows the same evidence you had rather than a conclusion you already reached.
  2. Separate mitigation from diagnosis out loud. State what you did to stop the bleeding (flag off, shed traffic, drain a lease, roll back a deploy) and say plainly that you did it before the mechanism was known, because those are two jobs with different deadlines.
  3. Establish blast radius in countable terms: how many tenants, how many writes, and crucially whether the effect was loss or only delay. An append-only revision table or a pending outbox row means the change survived and the projection was merely behind, which is a repair rather than a data-loss incident.
  4. Prove the mechanism instead of asserting it. Name the trace span that grew, the plan that flipped to a sequential scan, the lease that expired, plus one alternative you ruled out and the signal that stayed flat while you ruled it out.
Follow-up
  • What would you do differently in the first five minutes, given the same dashboard and no more information?
  • Which follow-up action did you deliberately not take, and why was dropping it the right call?

Turn a code review disagreement into a decision

easy
code reviewoptimistic concurrencycommunication

A colleague's change updates a row with UPDATE resource SET version = version + 1 WHERE resource_id = $1 AND version = $2 and treats an affected-row count of zero as a successful no-op. You read that as a silently lost update; they think returning 200 is friendlier to clients than returning a conflict. Describe how you have handled a review disagreement of this shape: what goes in the comment, when you leave the thread, and who decides. Then write the comment you would leave here, in under 80 words.

Approach
  1. Sort the disagreement before writing anything. A silently discarded write is a correctness claim about data; the choice between 409 and 412 is taste. Only the first justifies blocking a merge, and saying which one you are doing is most of the value of the comment.
  2. Make the claim reproducible in the comment itself with an interleaving rather than a principle: A reads version 7, B reads version 7, B commits version 8, A's predicate matches zero rows, A is told it succeeded and A's edit is gone.
  3. Offer the alternative with its cost attached: return 409 carrying the current version and the revision that won, so the client can re-read and re-apply. Note that automatic retry is not the fix, because a retry re-reads the winner's state and reapplies an intent formed against data that no longer exists.
  4. Apply an escalation rule you can state: two round trips on the thread, then a call, and the service's owner decides rather than the reviewer. A reviewer who cannot be overruled is a bottleneck with extra steps.
Follow-up
  • Where would you put the test that fails if someone reintroduces the swallowed zero rowcount?
  • The author says clients cannot handle a 409. How do you check whether that is true?
  • 01

    Describe a technical decision you made and later reversed. Pick one that cost something: a service you split and merged back, a cache you added and removed, an index you created that pushed the planner onto a worse plan, a projection you rebuilt from scratch. State what you believed when you decided, the measurement that changed your mind, how long the wrong version ran in production, and what the reversal cost in migrations, dual writes, and a deprecation window for callers you did not own.

  • 02

    Pick an incident you personally drove, ideally one where writes were affected rather than reads. In six to eight minutes: state the symptom as it first appeared on a dashboard, the blast radius you established before you knew the cause, the mitigation you applied and when, the mechanism you eventually proved, and the follow-up that would prevent a repeat. Bring numbers: error rate, tenants affected, minutes to mitigate, minutes to resolve. If you cannot name what you measured, choose a different incident.

  • 03

    A colleague's change updates a row with UPDATE resource SET version = version + 1 WHERE resource_id = $1 AND version = $2 and treats an affected-row count of zero as a successful no-op. You read that as a silently lost update; they think returning 200 is friendlier to clients than returning a conflict. Describe how you have handled a review disagreement of this shape: what goes in the comment, when you leave the thread, and who decides. Then write the comment you would leave here, in under 80 words.

PracHub preparation framework ↗
How difficult is the Software Engineer interview process at Lg Ad Solutions?

The process is highly rigorous and is widely considered difficult, especially during the system design and core algorithmic rounds. Preparing thoroughly for scalability challenges and low-latency constraints will significantly increase your chances of success.

Lg Ad Solutions Software Engineer candidate reports ↗
What programming languages should I use during the coding interviews?

You can generally use any modern programming language you are comfortable with, such as Python, Java, C++, or Golang. It is highly recommended to choose a language that you can write quickly and bug-free under time pressure.

Lg Ad Solutions Software Engineer candidate reports ↗
Does Lg Ad Solutions support hybrid or remote work arrangements?

Yes, Lg Ad Solutions offers flexible working arrangements depending on the specific team and location. Many engineering teams operate under a hybrid model, balancing remote productivity with collaborative in-office days.

Lg Ad Solutions Software Engineer candidate reports ↗
How long does the entire interview process take from start to finish?

The typical timeline from the initial recruiter screen to a final decision is approximately three to four weeks. This can vary depending on candidate availability and the scheduling of onsite panel interviews.

Lg Ad Solutions Software Engineer candidate reports ↗
What topics does Lg Ad Solutions test in interviews?

Lg Ad Solutions interviews most often cover SQL (query writing), System Design, Data analysis (case studies), Ad Tech Product Management, and Algorithms. The exact emphasis depends on the specific role you apply for.

Lg Ad Solutions Software Engineer candidate reports ↗
Sources & methodology 3 sources ↗

No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.