andreyka26_se
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Hey, I'm software engineer at Microsoft, with 8+ years of experience. Here we are talking about F(M)AANG big tech interviews: leetcode, system design and corpo life.

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When my MS colleagues are asking how am I doing at Snowflake.
β€¦πŸ˜†πŸ˜†

Disclaimer: the post is only for humour purposes, nothing in common with reality
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Sieve of Eraosthenes.

I have seen many problems on the Leetcode that require some work with prime numbers, either generating a lot of them, and checking whether some number is prime or not

Prime numbers are heavily used in encryption and hashing due to such math properties. So the usage is not only leetcode.

Prime number - is the number that is divided by itself and one without reminder. 0 and 1 are not prime numbers (proven by contradiction). Examples: 2,3,5,7,11,13,17,19...

===

The method, you can naively generate prime numbers up to N using O(n * sqrt(n)) by checking all possible factors. But the Sieve of Eratosthenes is much faster, close to linear O(log(logn))

For your understanding: log(log(10^9)) = 3.03

Check the comments and save this pattern to recall before the interview!
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Just reminder - I always read all the comments and react to them.

So you have real power to affect/influence the future content a lot.

I have added tags a bit, so it is easier to search for you. Will do separate post and pin it.
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andreyka26_se pinned Β«System design / Tech #systemdesign #network #security #auth Live #bigtech #healthcare Leetcode #daily #pattern #nopattern #recommendΒ»
Daily (273/373 streak until LC cap)

Dumb and irritating question. I hate this matrix shit when you need to struggle with these boundaries and indices. Don't recommend, however it is very straight forward.

https://leetcode.com/problems/cyclically-rotating-a-grid/submissions/1999151788/?envType=daily-question&envId=2026-05-09

#daily #medium #nopattern
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Today is amazing sunny day in Dublin.
But I am oncallπŸ₯²
Not that I would go out even if I am not oncall, but stillπŸ˜†
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AI is disaster and saver at the same time. I wanted to do my dev tools that I'm typically searching separately in chrome for a long time: guid, ip checker, dns, reverse dns etc

What I'm currently extensively using at work:
- ip subnet checker, omg, I wanted it for so long. I had many time when I have subnet, and needed to check single IP. Example: does 10.77.64.0/19 cover 10.77.96.1 -> answer no, but it is not easy to tell.
- ip checker, that additionally tells you which cloud provider and which region of that cloud provider IP belongs to (covers aws, azure, gcp and cloudflare). Usage: I want to check from the logs whether I'm paying for that traffic or not (cross cloud or cross region).
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andreyka26_se
AI is disaster and saver at the same time. I wanted to do my dev tools that I'm typically searching separately in chrome for a long time: guid, ip checker, dns, reverse dns etc What I'm currently extensively using at work: - ip subnet checker, omg, I wanted…
Not a marketing, I'm not making money out of any my public resources/websites/apps, just can be useful as it was for me if you are working with network/traffic or you are SRE

Everyone can do it within 10-20 mins, but in case you don't want to spend claude tokens on it, here you go: https://tools.andreyka26.com/ip-checker
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Daily (274/373 streak until LC cap)

Good reminder for DP pattern, not hard tbh, go and collect the coin.

https://leetcode.com/problems/maximum-number-of-jumps-to-reach-the-last-index/description/?envType=daily-question&envId=2026-05-10

#daily #medium
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Daily (275/373 streak until LC cap)

Easy problem without any pattern pretty much. Go and collect the coin it is 2 minutes problem

https://leetcode.com/problems/separate-the-digits-in-an-array/description/?envType=daily-question&envId=2026-05-11

#daily #easy #nopattern
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Let me share the pain, and tell you HOW NOT to do software engineering.

Skill number1 you should have over your service: being able to quickly understand that some specific merge to master/main is in some deployment or no.

Typical application: you merged some fix pr that changes behaviour, you have 20+ deployments that are deployed incrementally, and you want to know whether this specific fix is in the deployment you are interested in (lets say some oncall has paged you and moved to bridge call asking this q).

Usually you have 2 things:
- metric that reports version per deployment
- tag WITH THIS version on the main branch that represents the state of code that got deployed.
These 2 MUST be easily correlated. So version on the dashboard and version on the tag must be either the same or easily derivable.
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Now imagine, somebody created a service, that has version coming hell knows from where, git tags that contain completely different numbers and words comparing to version in dashboard, and here you go: some guy is asking you: can we check this thing is deployed to region X?

Guess how much time I spent to confirm it?
Did I confirm 100% in the end?
I as AI successful in helping answer these questions(has access to docs and git)?
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I’ll be honest, sometimes I feel warm nostalgic feeling to Epam and other outsource companies. Maybe I was lucky, but typically I had so small projects that I could have context ABOUT WHOLE project at a time.
You know everything e2e, you have FULL mental model in your mind.

I didnt have this feeling for 5 years nowπŸ˜†
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Daily (276/373 streak until LC cap)

The easiest "hard" problem implementation I have ever seen. Good problem, a bit hard to come up with intuition: check discussion tab.

My advice: try to think greedy: which task to process the first and what you want to have as the first task

https://leetcode.com/problems/minimum-initial-energy-to-finish-tasks/description/?envType=daily-question&envId=2026-05-12

#daily #hard #nopattern
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Daily (277/373 streak until LC cap)

Pretty hard problem, should be hard definitely. And solution is pretty unintuitive.

https://leetcode.com/problems/minimum-moves-to-make-array-complementary/description/?envType=daily-question&envId=2026-05-13

#daily #medium #pattern
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Daily (278/373 streak until LC cap)

For some reason didn't go from the first try for me today XD, maybe too much work at Snowflake.. But in general it is pretty easy

https://leetcode.com/problems/check-if-array-is-good/description/?source=submission-noac

#daily #easy
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All this time I was trying to understand how vibe coding feels like to me and in general how my working day looks like.

Pretty accurate
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