Daily (236/373 streak until LC cap)
Today is typical solid DP problem that you might be asked during real interview: definitely advise to solve.
https://leetcode.com/problems/maximum-amount-of-money-robot-can-earn/description/?envType=daily-question&envId=2026-04-02
#daily #medium #pattern
Today is typical solid DP problem that you might be asked during real interview: definitely advise to solve.
https://leetcode.com/problems/maximum-amount-of-money-robot-can-earn/description/?envType=daily-question&envId=2026-04-02
#daily #medium #pattern
👍4❤2
Leant bisect left/right operations in python, never used them before.
For those who need to remind themselves or learn from scratch as I did.
yes these are screens from gpt, but it is third attempt to explain it with simple visual examples (I told him I'm dumb, it helped xD)
For those who need to remind themselves or learn from scratch as I did.
yes these are screens from gpt, but it is third attempt to explain it with simple visual examples (I told him I'm dumb, it helped xD)
❤4
Daily (237/373 streak until LC cap)
Pretty hard and cumbersome problem, tbh it feels pretty large to reason about and effort consuming to reason about, but definitely not bullshit problem either. Up to you whether to solve it or not
https://leetcode.com/problems/maximum-walls-destroyed-by-robots/description/?envType=daily-question&envId=2026-04-03
#daily #hard
Pretty hard and cumbersome problem, tbh it feels pretty large to reason about and effort consuming to reason about, but definitely not bullshit problem either. Up to you whether to solve it or not
https://leetcode.com/problems/maximum-walls-destroyed-by-robots/description/?envType=daily-question&envId=2026-04-03
#daily #hard
👍2
IMPRESSIVE. Claude pushed me back instead of hallucinating / bullshiting. Eventually they did it, I'm surprised in a good way.
Wondering how they did it, typically some months ago even explicit instructions to push back instead of bullshiting with temperature = 0 would still result in hallucinating rather than getting pushed back
Wondering how they did it, typically some months ago even explicit instructions to push back instead of bullshiting with temperature = 0 would still result in hallucinating rather than getting pushed back
❤4
Now legit I'm getting really annoyed and tired by this daily nonsense shit.
I started interviewing in Snowflake lately, and I see what people are getting asked. OMG for couple of times I was shadowing the interviewer for some senior positions. I cannot even explain how easy the questions they ask seem to me now after seeing this nonsense crazy bullshit daily leetcode problems.
I really don't know why other people are solving it consistently, and are there a lot of such people who don't miss single streak like me?
Leetcode really DOES have good problems, but they are all in lists, so usually they are top 500 first problems. 90% of daily - is ugly nonsense that no one would ask ever, and if so - fuck such company
===
Once I'm getting cap (4 months left) - I will be solving only exciting, interesting, applicable problems with measurable complexity (that you are able to solve in 1 hour, NOT FUCKING 1 HOUR TO ONLY UNDERSTAND THE SOLUTION)
I started interviewing in Snowflake lately, and I see what people are getting asked. OMG for couple of times I was shadowing the interviewer for some senior positions. I cannot even explain how easy the questions they ask seem to me now after seeing this nonsense crazy bullshit daily leetcode problems.
I really don't know why other people are solving it consistently, and are there a lot of such people who don't miss single streak like me?
Leetcode really DOES have good problems, but they are all in lists, so usually they are top 500 first problems. 90% of daily - is ugly nonsense that no one would ask ever, and if so - fuck such company
===
Once I'm getting cap (4 months left) - I will be solving only exciting, interesting, applicable problems with measurable complexity (that you are able to solve in 1 hour, NOT FUCKING 1 HOUR TO ONLY UNDERSTAND THE SOLUTION)
🔥9
Daily (238/373 streak until LC cap)
Today is not bad problem. First of all it is some real concept from computer science (I didn't know before). Second of all it is not that hard to be honest.
https://leetcode.com/problems/decode-the-slanted-ciphertext/description/?envType=daily-question&envId=2026-04-04
#daily #medium
Today is not bad problem. First of all it is some real concept from computer science (I didn't know before). Second of all it is not that hard to be honest.
https://leetcode.com/problems/decode-the-slanted-ciphertext/description/?envType=daily-question&envId=2026-04-04
#daily #medium
👍3
So, it is the time. Do you want to try yourself for System Design? You remember I said I don't know the good real prod solution for Messenger System Design?
It is time to shine and give your ideas, while I'm prepping the article, so that I can consider all the possible ideas and challenge them whether they are scalable or no.
It is time to shine and give your ideas, while I'm prepping the article, so that I can consider all the possible ideas and challenge them whether they are scalable or no.
👍7
So, VERY SIMPLE SCENARIO:
- we have chats, and users per chat
- only users that have currently opened chat are depicted, we don't care about chat list updates
- we don't care about encryption, let's assume we send plain data, as TG does btw for nonsecret chats
- we have chats, and users per chat
- only users that have currently opened chat are depicted, we don't care about chat list updates
- we don't care about encryption, let's assume we send plain data, as TG does btw for nonsecret chats
❤2
In the system design diagram there are:
- 3 chats,
- every chat has 4 users.
- GW -> socket gateway server that handles client's socket.
- Chat API is separate for simplicity to not cover processing of the messages on the GW itself
You can see that if we have much larger participants count than number of GW nodes we end up every GW node handle ALL large chats, thus causing broadcast.
===
This is one of the canonical solution that I saw on the internet for Messenger: you connect user to random GW and this GW gets (somehow) the message to deliver to the users that are connected to it. The solution is actually the way it works in Telegram and other Messengers, you have only single socket connection, it does not change when you switch chat.
First screen: 2 GW, 4 users per large chat => 4 / 2 = 2 users on EACH GW for EACH large chat
Second screen: we scaled GW nodes by 2 = 4 GW nodes -> and it didn't fix the broadcast, thus non linearly scalable
- 3 chats,
- every chat has 4 users.
- GW -> socket gateway server that handles client's socket.
- Chat API is separate for simplicity to not cover processing of the messages on the GW itself
You can see that if we have much larger participants count than number of GW nodes we end up every GW node handle ALL large chats, thus causing broadcast.
===
This is one of the canonical solution that I saw on the internet for Messenger: you connect user to random GW and this GW gets (somehow) the message to deliver to the users that are connected to it. The solution is actually the way it works in Telegram and other Messengers, you have only single socket connection, it does not change when you switch chat.
First screen: 2 GW, 4 users per large chat => 4 / 2 = 2 users on EACH GW for EACH large chat
Second screen: we scaled GW nodes by 2 = 4 GW nodes -> and it didn't fix the broadcast, thus non linearly scalable
🔥5
andreyka26_se
In the system design diagram there are: - 3 chats, - every chat has 4 users. - GW -> socket gateway server that handles client's socket. - Chat API is separate for simplicity to not cover processing of the messages on the GW itself You can see that if…
chat.excalidraw
165.4 KB
Please let me know about your ideas, as today-tomorrow I plan to finish the article, so that you can test your idea as well, as I gonna write bunch of simulations, calculations, POC etc.
In case someone would want to play with diagrams, attaching excalidraw for the diagrams
In case someone would want to play with diagrams, attaching excalidraw for the diagrams
🔥3
Daily (239/373 streak until LC cap)
Easy and 'free' problem basically, you need 30 seconds for it
https://leetcode.com/problems/robot-return-to-origin/description/?envType=daily-question&envId=2026-04-05
#daily #easy #nopattern
Easy and 'free' problem basically, you need 30 seconds for it
https://leetcode.com/problems/robot-return-to-origin/description/?envType=daily-question&envId=2026-04-05
#daily #easy #nopattern
👍3
andreyka26_se
In the system design diagram there are: - 3 chats, - every chat has 4 users. - GW -> socket gateway server that handles client's socket. - Chat API is separate for simplicity to not cover processing of the messages on the GW itself You can see that if…
Other way to show it. In this diagram (screen 1), we have only 1 chat with 4 participants per chat and 1 message per second coming to this chat from one of the clients (out of scope).
Do you see it? Every WS Gateway have to process all messages, as chat participants are connecting randomly (or deterministically but based on user_id property).
From now on, unless number of WS Gateways is more than max number of participants in chat - it will always be the case. Check screen 2, number of nodes = 5 > participants per chat = 3 (top 3 clients => chat1, bottom 3 clients => chat2). Now WS gateways process 1 message per second, except WS Gateway1, because he has users from both chats.
Screen 3 - is the same scaled situation but with single chat
Do you see it? Every WS Gateway have to process all messages, as chat participants are connecting randomly (or deterministically but based on user_id property).
From now on, unless number of WS Gateways is more than max number of participants in chat - it will always be the case. Check screen 2, number of nodes = 5 > participants per chat = 3 (top 3 clients => chat1, bottom 3 clients => chat2). Now WS gateways process 1 message per second, except WS Gateway1, because he has users from both chats.
Screen 3 - is the same scaled situation but with single chat
🔥6
Daily (240/373 streak until LC cap)
Today is good problem, not bullshit, I like when it has some sort of simulation and objects to play with.
https://leetcode.com/problems/walking-robot-simulation/description/?envType=daily-question&envId=2026-04-06
#daily #medium
Today is good problem, not bullshit, I like when it has some sort of simulation and objects to play with.
https://leetcode.com/problems/walking-robot-simulation/description/?envType=daily-question&envId=2026-04-06
#daily #medium
❤5