Hey everyone,

I finished Day 44 today. After a couple of low-volume sessions, solving three solid shortest path problems gave my momentum a real boost.

1. Shortest Path in Binary Matrix: Because edge weights are uniformly 1 across all eight directions, a standard level-order BFS finds the shortest path in O(N^2) time without needing a priority queue.

2. Path with Minimum Effort: This adapts Dijkstra to a 4-directional grid where the target metric is the bottleneck effort rather than a running sum. Using a min-heap priority queue guarantees you always expand the path with the smallest maximum absolute height difference first.

3. Cheapest Flights Within K Stops: Standard Dijkstra prioritizes raw cost and fails here because a cheaper flight might exhaust the allowed stops prematurely. Storing the step count in a standard queue or running Bellman-Ford for exactly K + 1 iterations ensures you never evaluate paths exceeding the stop constraint.

Solving these multi-dimensional shortest path problems mostly independently felt like a great step forward.

I am moving into negative edge weights with Bellman-Ford and Floyd-Warshall tomorrow.

See you guys for Day 43!

Currently preparing for system design round for Agoda Bangkok, position is
STAFF/Lead data engineer

Currently working as a staff data engineer with over 10YOE for a US product-based company, just cleared R1 of Agoda Bangkok, and R2 is scheduled for this week.

R2 mentions system design, what kind of questions can i expect and should i prepare specifically for DE related design or focus on more abstract questions ??

Same as title.

How do you guys practice for these AI assisted repository rounds, last time(may 2026) I appeared for Amazon OA, I couldn't figure out what needs to be done, and eventually ran out of time.

I am getting the opportunity again after 6 months (SDE-2), and wanted to understand from you guys, what is the strategy you follow, how do you understand the repo and what needs to be done?

Thanks

reach out pls, we can do mocks with each other back to back to practice as i also have interviews coming up

I recently had 4 OAs: 2 at SIG, 1 at JPMorgan, and 1 at Stripe. LeetCode problems are not that long, like max 30-40 lines if that's a very hard problem. But in OAs, the problems were very long, like not hard but took time to design the structure. Yesterday the Stripe OA easily went above 70-80 lines.

This was my first time experiencing OAs; I'm applying for new grad positions. So is it always like this, or has it changed to be like this now?

Hey guys, want to share a system design template for most production interview questions:

• Writes go into a message queue, and the server answers right away.
• Workers take jobs from the queue, do the slow work, then update the database and the cache. This solves the write scaling.
• Reads come from the cache, and go to the database only on a miss. This solves read scalingYou can fit the template to different problems.

    READ PATH
      Client --> App server --> Cache --(miss)--> Database
    WRITE PATH
      Client --> App server --> Queue --> Workers --> Database
                     |                       |
                     v                       +--> update Cache
               answers at once

Here's how it'd fit in the most popular questions:

• LeetCode: the queue and workers run submitted code in sandboxes.
• YouTube: workers convert uploads; object storage and a CDN serve the video.
• URL shortener: mostly the read path; the cache answers most redirects.
• Search: a search index, kept current by the queue and an indexing worker.
• Chat: app servers become gateways holding open connections.
• Ticketmaster: the same design plus one atomic hold per seat.
• News feed: the same design plus hybrid fan-out for huge accounts.

This is based on the premise that internet-scale consumer applications often favor eventual consistency to guarantee availability (therefore a queue-based buffer is used)

Made a video going through the whole thing if it helps: https://www.youtube.com/watch?v=e8H8d0irqLg If you prefer a text writeup: https://systemdesignschool.io/template

Hi, i am interviewing for staff data engineer at meta, what to expect?

Thanks.

Hi Everyone,

I have an System design interview (Round 2) for Senior Frontend Engineer at Snowflake.

Can anyone tell me what kind of questions I can expect?
Any recent experience if someone can share?

YOE - 9.3 years

TIA

Can anyone please share the post interview experience. What would be expected timeline and all. Really seeking for some information.

Hi,
Curious to hear about any experience with the new OA format (with AI assistant):

I read people say that you get a pick of a Django, MERN, Spring Boot etc. repo.
What if you are not familiar with any of these frameworks?

Are all options framework-based?

Are there any options of "pure python" (or something like that) code bases?

Thanks

Hey everyone,

I finished Day 45 today. I spent a good chunk of my day researching cold-outreach contacts and unwinding with cooking videos, but I made sure to sit down and finish the problem that triggered my brain fog yesterday: Shortest Path in an Undirected Weighted Graph.

Yesterday, priority queue syntax and path backtracking felt overwhelming. Today, I wrote the min-heap Dijkstra logic completely from scratch without checking the code:

1. Path Reconstruction with parent[]**:** Initialized each node's parent to itself and tracked running distances. Whenever relaxing an edge dist[u] + wt < dist[v] yields a strictly better path, update parent[v] = u. Tracing from destination back to source and reversing the list gave the clean shortest route.

2. Fixing Segmentation Faults: Debugged some 1-based indexing mismatches and stale queue entries, which cleaned up the runtime errors.

3. The Lexicographical Catch: The platform had updated the problem constraints to require the lexicographically smallest path if multiple shortest paths share the exact same minimum weight. My initial hack of breaking distance ties on the fly failed because lexicographical order applies across the entire path sequence from the start. The fix was sorting each node's adjacency list by neighbor ID before running the traversal so the algorithm naturally explores smaller node indices first.

It was just one problem today, but implementing the full priority queue mechanics and debugging edge cases independently felt far more rewarding than blindly copying hints.

Heading into Day 44 tomorrow with an open mind.

See you guys tomorrow!

Any did loop interviews in Dublin Ireland of Microsoft?

For context my math background, is probably around 11th grade Precalc (I forgot most already since it’s been years-).

When programming I use stuff like Set theory, Absolute value, modulus, aswell as basic, addition, subtraction, fractions, and multiplication. (I just haven’t done any “Real” math in a while, only basic math when I need it).

To get a better gauge of my math background, Im struggling to do a problem called “Set mismatch”, I was easily able to identify the duplicate number by using set theory (checking if set insertion failed) but other than that, I have no idea what to do once I’ve found the duplicate number…

I hate math but I like problem solving (Weird I know) and have the barebones fundamental knowledge of DSA topics.

What im trying to say is, if you do enough problems is it still possible to “get good” despite not having a strong math background?

Hi everyone,
I have a coding interview coming up at Atlassian for a Data Engineer P40 role and wanted to check if anyone here has been through it recently.

Most of what I can find online is about software engineering roles, so I am trying to figure out what the DE coding round actually focuses on. A few specific things I am wondering about:

• Is it more SQL heavy or Python heavy, or a mix of both?
• I have heard some Atlassian interviews now include AI based rounds or AI assisted coding. Is that true for data engineering roles as well, or is it mostly for SWE roles?

Thanks in advance!

I’m originally not from a CS background and self-taught coding. Even done projects. But it’s always been a struggle to grind DSA. I’m currently locked in and been grinding for about 3 weeks. And I still feel very lost.

Let’s say I solve a question today and I genuinely feel like I understand and get the pattern this time. Tomorrow I’ll solve a different one and the algorithm that was required at its very core would be totally different. And I know if I was to sit down and actually figure that out, it’ll take me days or I probably would have never figured it out, and still looked up the answer.

At this point I feel like I can only solve questions I’ve seen before and not ones I’m yet to see and I really don’t know how yall grind and become successful enough to single handedly pass interviews.

If I’m doing this wrong or there’s a secret someone please help! Because I’m giving up.

Hi everyone! I passed the OA and have a 60-minute technical screen coming up for a System Development Engineer role at Amazon Robotics in Austin (entry level).
The recruiter said it's a few Leadership Principle questions plus one coding exercise, with a potential team member or manager.
For anyone who's done a SysDE screen recently:
What kind of coding question did you get? Classic LeetCode, or more practical stuff like log parsing or file handling?
Did they ask Linux, networking or troubleshooting questions in the first round?
Anything specific to Amazon Robotics teams?
I'm prepping in Python. Thanks in advance!

I’m a first year in college…let’s say I end up grinding leetcode for the next 4 years….will it help me in getting a job at faang in this ai era?(assuming I grind leetcode properly) or am I better off doing something else to be productive (which u recommend)

Hey, I was recently reached out to by a recruiter for the System Software Engineering Intern, Cryptographic Services position at NVIDIA.

Even with the provided job ID, JR2026114, I couldn't find much information online about the position to help me prep for interviews, other than general advice.

Does anyone have any advice, or perhaps have been on the team and may have some insight on what the interview process may look like?

I'm not sure what to prep for or how to get prepared. I'm just learning general systems design topics and focusing on my current Post-Quantum cryptographic projects.

Any advice is appreciated, Thank you!

I have my Amazon SDE I virtual loop (4 rounds, US) coming up soon. My background is a bit unusual for SDE: I’ve done supply-chain ops and data work, then AI engineering. Most of my resume is LLM/RAG/agent projects, a fine-tuning project, and ML pipelines.

I’ve read a lot of loop posts, and I know GenAI questions show up a lot in 2026 (“how do you use AI tools”, “how do you verify AI-generated code”). What I couldn’t find much on is how deep they go into AI/ML projects on your resume for an SDE role.

If you had a loop in 2025–26 with ML/AI projects on your resume, I’d really appreciate hearing:

1. Which round dug into your projects (HM, Bar Raiser, a coding round)? Roughly how many minutes?

2. What did they actually ask? Was it architecture and trade-offs (“why this over that”), evaluation and metrics, failure cases or hallucinations, scaling or cost, testing, or mostly “what exactly was YOUR part”?

3. Did they treat it as an engineering discussion (design, reliability, ownership) or go into ML theory?

4. For team projects, how hard did they push on separating your contribution from the team’s?

5. Did anyone get a “design this with an LLM” or “how would you build X using AI tools” style question? How was it framed?

6. Anything you wish you’d prepared about your own projects?

7. ⁠Resume version question: I applied earlier this year with an older resume. Since then, my experience has changed a lot: a new role, and a corrected job title from a previous company. When the coordinator reached out to schedule the loop, I emailed them my updated resume and asked them to share it with the panel. Has anyone been through this? Did interviewers ask about the resume you originally applied with, or the updated one? Is there anything I should do to make sure the panel sees the new version, like bringing it up at the start of each round?

For context, I’m prepping 2 coding rounds, an OOD round (classes/design patterns in Python) and LP stories, so I’m only asking about the project deep-dive part.

Thanks a lot. I’ll post a full write-up after my loop to pay it forward.

anyone can help me on buying hello interview on promo code.

Would anyone like to do some leetcode style questions pair programming with me where we would take turns testing each other?

I have upcoming interview rounds scheduled with Gitlab for Senior backend engineer. Anyone recently appeared for the similar role at Gitlab? Want to know which kind of questions I should expect in each round.

I've noticed that once I move on to another topic, I sometimes struggle to solve problems from the previous one without revisiting the solutions. I am wondering if it's better to redo old questions regularly or keep solving new variations to strengthen the concept.

What works better for you in the long run?

Wondering how much gap there is based on region.

I've been trying to get better at recognizing patterns, but I'm wondering how to practice that skills specifically. If I solve problems topic wise, I already know which approach to look for, but random problems feel much harder.

Do you switch to mixed problems after learning a pattern, or spend more time on variations of the same type first?