Now the question,
Can you tell me, why we might need NAT GW in this AWS infra topology? Why not just usiong ec2 -> IGW hop, and what can be the benefit of it?

Daily (266/373 streak until LC cap)

Pretty easy one today, without any pattern.
Hint for understanding: imagine it as digit clocks (see the comment for the picture)

https://leetcode.com/problems/rotated-digits/description/?envType=daily-question&envId=2026-05-02

#daily #medium #nopattern

So you left very good points, and they are all correct.
I will just extend them by one thing:

If we would skip NAT GW, we will need to buy public ip FOR EACH ec2 instance. With NAT GW, we can just buy single IP and assign it to NAT GW, then saving on IPs for each ec2 behind it.

Daily (267/373 streak until LC cap)

Easy one, go and collect the coin. It has 2 optimized solutions that you might want to know (at least one).

https://leetcode.com/problems/rotate-string/description/?envType=daily-question&envId=2026-05-03

#daily #easy #pattern

I thought that AI would replace QAs the first (I am backend + SRE, 8years exp, ex-Microsoft).
Now I believe QAs might be needed more than software devs. Talking about small projects, I am mostly vibe coding, and even stopped checking the code. I am just validating end result (qa job). It doesn’t worth it to build test infra, as you WILL need to manually check it is corect. So as experienced engineer I am doing around 20% of SWE job and 80% of QA job…

Ai is good at producing stuff, but can hallucinate, so responsibility and validation is still needed to be done by human. For big projects in big tech, mostly you would have tests, but for small stuff, sorry, but typically you just need to maually validate stuff, as it is cheaper and faster without risks of losing reputation.

As promised:

https://www.youtube.com/watch?v=9-5U3TwxS1c

#systemdesign

Daily (268/373 streak until LC cap)

If you were into Leetcode at least a little bit - you have probably solved it at least once.

You need to know the trick unfortunately to solve it easily and fast.

https://leetcode.com/problems/rotate-image/?envType=daily-question&envId=2026-05-04

#daily #medium #nopattern

Once one guy on this telegram channel has shown me this free 10 coins per week, showing it to you as well. On the beginning of each week, any time during that week you can go to "contest" tab and click on this small button once a week -> it will give you free 10 leetcode coins.

Started posting there 4-5 months ago. I would expect 20 subs max (5 of them are my friends), but it goes well, thanks Meta

https://www.threads.com/@andreyka26_se/post/DX7FKS6jEp_?xmt=AQF05kDn1LVTNVr_8hDQzzPe1uHHm7NKcblFtkvawK67ACUmONxzBNesJ_IKvYiIZ-x6yMxR&slof=1

Comparing to X ahahah, greedy Musk wants me to pay for blue check box (it aint happening)

Daily (269/373 streak until LC cap)

Is it nostalgia week?))
Solid problem, but a bit annoying, they might have done it much more interesting, check the comments I will explain.

https://leetcode.com/problems/rotate-list/description/?envType=daily-question&envId=2026-05-05

#daily #medium #pattern

Daily (270/373 streak until LC cap)

Not bad problem, not hard, but no specific pattern eaither.

https://leetcode.com/problems/rotating-the-box/description/?envType=daily-question&envId=2026-05-06

#daily #medium #nopattern

Daily (271/373 streak until LC cap)

For me it was hard problem, from intuition standpoint. Didn't get the right one, until looked at the solution, but problem does not seem to be a bullshit.

https://leetcode.com/problems/jump-game-ix/description/?envType=daily-question&envId=2026-05-07

#daily #medium #pattern

When my MS colleagues are asking how am I doing at Snowflake.
…😆😆

Disclaimer: the post is only for humour purposes, nothing in common with reality

Daily (272/373 streak until LC cap)

This is yesterday's daily, as I needed to learn new concept and understand solution well, as it is for "staff", it is not bullshit mostly, and it has multiple very useful patterns.

https://leetcode.com/problems/minimum-jumps-to-reach-end-via-prime-teleportation/description/?envType=daily-question&envId=2026-05-09

#daily #medium #pattern

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!

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.

System design / Tech
#systemdesign #network #security #auth

Live
#bigtech #healthcare

Leetcode
#daily #pattern #nopattern #recommend

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