Hello Tildes,

I am currently taking DSA in college and struggling a lot with the math and algorithms. Recently had to solve Karatsuba questions and I don't even know what I wrote down on the paper. I have been trying to look for videos on this and only really came away with a vague understanding.

What I've noticed is that I struggle with solving the math part of the questions.

For example: "Describe a divide and conquer algorithm to compute the square
of an n-digit integer in O(n log3 5) time, by reducing to the squaring of five [n/3]-digit
integers"

I have zero clue how I am supposed to understand the latter half of the question. It makes no sense to me beyond I am supposed to be multiplying squared numbers. How do I even begin to turn this into an algorithm? What is the solution even supposed to look like?

Needless to say, I've struggled with math my entire life and I've been trying for years to be decent with it, and I have nothing to show for it.

So, do you have any recommendations that could simplify the math needed for DSA? Videos are preferred but I will textbook recommendations as well.

Thank you, and have a good day!

(That title is kind of awkward, feel free to suggest a better one.)

I came across aini's channel on Youtube a while back. She does videos on different topics focused on East Asia. Her most recent video being "Why Chinese People Will Choose $5 Over $10".

I'm especially interested in native creators; those who can present a personal view from the inside. Even more so for countries that are not as well-covered for whatever reason—like places with less technological access or government limitation.

My own preference is for a more analytical presentation. I.e. looking through an academic lens incorporating sociology, psychology, etc, rather than "footage of daily life". That style is still welcome, of course!

Recently my daughter (third grade) has started learning to type at school. It's a Montessori program, so it's a pretty low tech environment overall, which I mention because I don't necessarily expect them to have a nuanced view of technology issues.

One of the typing programs they use is nitrotype.com, which adds a competitive gameplay element. However, it also has mechanism to friend another player. Friends can only communicate with stock phrases, so there's not too much "Internet leakage" beyond being able to choose a username.

I set it up for my daughter on her Linux Chromebook (I whitelist things I want her to have and everything else is blocked at DNS). Seeing her interact with it the first time, I realized that she spends as much time "adding friends" as doing the typing.

On its face, this activity is pretty harmless. But I am worried about the patterns it might be creating for her. I'm worried about her uncritically engaging with the dopamine hit of getting a new friend. Or how it shapes her idea of how many friends she has or where idea of her self worth comes from. Or what she thinks friends are.

So after that long preamble, here are some questions:

• How would you explain "friends" in this context?
• Would you distinguish them from other kinds of friends, either real or virtual?
• Would you attach a moral component to the activity? E.g. that it is good/bad or helpful/harmful
• How would you frame it to the teacher? Not so much in terms of whether or not they should do it in the classroom, but what kinds of conversations should they be having about the friends experience?
• If I'm asking the wrong questions, what questions should I be asking instead?

I'm really interested in seeing the perspectives people have on this. My own ideas are a bit murky, but I will put them down as a comment.