andreyka26_se
606 subscribers
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Hey, I'm software engineer at Microsoft, with 7 years of experience. Here we are talking about F(M)AANG big tech interviews: leetcode, system design and corpo life.

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Daily (114 day streak)

Hard, and it is hard, especially to build an intuition. But in the comments I will leave the hints that helped me to build mental model

https://leetcode.com/problems/maximum-running-time-of-n-computers/description/?envType=daily-question&envId=2025-12-01

#daily #hard
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Daily (115 day streak)

Nice problem. I found out that I really like when leetcode problem has something physical or semi physical. Today it is geometry and trapezoids. However some simple math is used here.


https://leetcode.com/problems/count-number-of-trapezoids-i/description/?envType=daily-question&envId=2025-12-02


#daily #medium
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After 1 month of procrastinating and writing in background, it is eventually out. I guess this is the most detailed article about Stripe System Design.

Please leave your thoughts about the decisions made in the design and overall about the article.

https://andreyka26.com/payment-gateway-stripe-system-design-with-microsoft-engineer
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For technical articles I think that will be it. We are starting soon writing about leaving Microsoft, about relocation to Ireland, about Snowflake, etc.

You gonna have the link the first ofc
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Tomorrow is fun:
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Daily (116 day streak)

One of the rare cases, where problem is hard, I didin't solve it on my own, but I really liked it. Hints, geometry and intuition are in the comment section

https://leetcode.com/problems/count-number-of-trapezoids-ii/description/?envType=daily-question&envId=2025-12-03

#daily #hard
How to check that lines are parallel?

1. Calculate vectors out of coordinates
dx = x2 - x1, dy = y2 - y1 => vector = (dx, dy)

2. Calcualte a slope = dy / dx.

3. any two lines that have the same slope (dy/dx) are parallel

#math
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How to check that two vectors are collinear (share the same line)

The idea behind is to calculate where both vector would intercept Y axis.
We can do it using line formula y = kx + b. For every single point in all vectors we know x, y, k = dy / dx. From these values we can find b

#math
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Daily (117 day streak)

Interesting problem, I wouldn't say it is hard, simulation will work, the trick here to write a good simulation, or figure out smart algo

https://leetcode.com/problems/count-collisions-on-a-road/description/?envType=daily-question&envId=2025-12-04

#daily #medium
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