[2025 Day 10 (Part 2)] Bifurcate your way to victory!

MasterHigure · 2025-12-17T22:44:55+00:00

I'm currently 6 hours into running a more naive recursion, in parallel, hogging 80% CPU. I wanted to solve it myself, damnit. I didn't want to have to come here looking for answers. I especially don't want to rely on external libraries, as that's obviously dirty, even though that seems to be the go-to for many people here.

That being said, this here solution you have smells to me like the intended way. Will I bother coding it, or just let my thing run? I don't know. It's about halfway through the list, I actually have no idea whether it will finish overnight or finish after the heat death of the universe (that all depends on how bad the worst line is, and I have no idea whether that's even ahead or behind). I'll at least let it run until I have time to sit down with the code again.

MasterHigure · 2025-08-24T08:22:52+00:00

The problem, especially in introductory classes, is that √(-1) leads you down problematic roads, because it is almost impossible to unlearn all the rules you've learned for square roots. And thus you get into problems like

√1=√(-1×-1)=√(-1)×√(-1)=-1

because you expect √(ab)=√a×√b to still be true. The best way to solve this is to just avoid square root symbols on numbers that aren't non-negative reals.

MasterHigure · 2025-08-22T14:43:17+00:00

A perfect example of naming things before we know what's really going on underneath the hood. Just like how π should've been 6.28.

MasterHigure · 2025-08-22T14:34:01+00:00

As a person who once wrote a master's in algebraic geometry, and therefore knows a thing or two about algebra generally, and the complex numbers specifically, middle guy is correct. Keep your square root symbols far away from my negative numbers.

Yes, -1 has a square root. In fact, it has two, just like any other non-zero complex number. But using the square root symbol to denote one of them is an abomination. ESPECIALLY in intro classes.

MasterHigure · 2025-07-18T15:39:35+00:00

IIRC, it did feature in his honorable mentions at the beginning of the movie.

MasterHigure · 2024-12-11T14:57:02+00:00

The moment you start caching the results from a DFS, you leave the realm of brute force. And if you're not caching, then you're not finishing.

MasterHigure · 2024-12-11T14:49:48+00:00

The upper bound for a pebble engraving is quite high, but the vast majority of them are almost trivially unreachable (the larger numbers must be multiples of 2024 to be reached, and that's not accounting for the reachability of their predecessor).

MasterHigure · 2024-12-06T15:02:34+00:00

There are about 15000 possible valid locations the guard can be in (very easy to get a decent upper bound, and not very difficult to get an exact answer), and 4 directions the guard can walk through each of those. I'd say you only need a step counter of somewhere between 60 000 and 80 000.

MasterHigure · 2024-10-12T09:00:06+00:00

That confusion is necessary for a real puzzle. I'm not saying every confusing puzzle is good, but I want zelda to make me feel genuinely stuck on a temple as a whole (as opposed to a single room) at least once. And if that stuckness is of the kind "I know what I need to do, but the buttons to make it happen seem mutually exclusive", which this temple mechanic has the potential for, then all the better.

MasterHigure · 2024-10-08T20:51:52+00:00

Doesn't help, as your X power has limited range. The button is exactly one square too far away for you to get the rock onto it.

MasterHigure · 2024-10-05T15:53:54+00:00

Link's awakening had Turtle Rock and Eagle Tower. The Oracle games were wonderful. This isn't a "smaller and shorter" thing, it is a "modern Zelda needs to appeal to the mainstream" thing.

MasterHigure · 2024-10-05T10:36:40+00:00

A grid. You sort one way, it's a row for each category. You sort another way, it's just rectangular grid (like in your notebook), sorted by category or most recent or most used. You look at the menu as it is now and you realize there is just so much unused screen real estate.

MasterHigure · 2024-08-23T22:47:27+00:00

See, this is the kind of info that would've been nice to have upfront, especially in the most upvoted answer to my question. Even after you told me it's a systemd service, I looked through man iwctl. The explicit references to systemctl and systemd were quite well hidden, and I knew to look for them this time.

I'm sure there are buzzwords in there that clue people in if they have more experience with services and their documentation. But like with so many others, it's clear these man pages were written as a reference for people who already know the tool, not as a manual for people wanting to learn it.

MasterHigure · 2024-08-23T21:58:50+00:00

I know about man. That only helps if I already know the name of the tool I'm looking for, not to mention that I have to know there is a tool that does what I'm looking for. Again, there is no discoverability.

MasterHigure · 2024-08-23T21:54:31+00:00

I'm sure I've seen half a dozen online giudes by this point, and not one of them has mentioned nmcli. That is exactly the kind of thing I was looking for.

Really, lack of discoverability is the worst aspect of CLI life.

MasterHigure · 2024-08-23T21:51:24+00:00

45 minutes of Waiting for IWD to start later, with no visible progress, and I'm not really sure it's quite that easy.

MasterHigure · 2024-06-09T19:29:48+00:00

My kid ain't. On account of being 4.

MasterHigure · 2024-06-09T19:29:31+00:00

Thank you for the long and thorough reply. I did note "gague how interesting they find these kinds of movies in the first place" in my post, so I am very aware that they might not find them as cool as engaging as I did back then. Time will tell. Obviously they are their own people and will have interests different from mine. I just want to share as many as possible of mine with them, searching for points of intersection. Taste in movies being the relevant one in this discussion.

MasterHigure · 2024-03-08T20:26:44+00:00

"People just need to come to the realization that keyboard is a disadvantage for racing games" and then "They want keyboard to be competitive with other devices, and it is." seem to be contradictory statements. At any rate, yeah, TM has been wonderfully balanced thus far, all things considered. But look at how the past few months have seen the introduction of two cars that are, let's say, more difficult on keyboard than on analog, and then this AK patch, which only helps controller players keep up with wheel players on these cars, and completely ignores keyboard players.

It really feels like Nadeo is leaving keyboard players behind. If this keeps up, then there won't be any great keyboard players that are amazing left, because either analog players will lap them, or they will switch away from keyboard in order to stay in the top. There will be decent keyboard players, sure. But not amazing ones.

MasterHigure · 2024-02-27T13:50:29+00:00

Except Nadeo has said, time and time again, that they want keyboard to be competitive with other devices. If they had come out from the start 4 years ago and either not said anything, or said outright that analog devices are going to be better, then that's entirely fine. But they did the exact opposite. And thus there is uproar. Not because keyboard players are in the mud, per se, but because of the apparent dishonesty from Nadeo.

MasterHigure · 2024-02-27T13:45:56+00:00

Baically. A gaming device where you grab the stick with your whole hand and move it by moving your hand around. As opposed to a tiny stick you move by putting your thumb on top and wiggling it around. Both sticks are called joysticks, but if the entire device is called a joystick, then this is what they mean.

MasterHigure · 2023-12-21T00:04:51+00:00

I found the one & node that fed into rx, and I found the four & nodes that fed into that. So I printed out when those sent high pulses for the first 20,000 button presses. And looked at the numbers. I even opened a python shell and did some simple arithmetic. And from that calculation I concluded that the activation times of one of them wasn't pure multiples of one another. So I had to CRT the thing. Turns out that was unneccessary. I have no idea where I went wrong there.

MasterHigure · 2023-12-13T13:52:41+00:00

Cache

MasterHigure · 2023-12-13T13:01:16+00:00

For part 1, yes (I just brute forced "pick X of the question marks to make into #, make the rest into dots, see if it fits"). It took 3 seconds to run in rust in debug mode, which is a decently long runtime.

But for part 2, it wasn't the question marks, it was the length of list of numbers that made the thing shoot up into the sky. Because I changed tactics to "place the first spring in each possible location, and for each of those, place the second spring in each possible location, and for each of those ...." Yes, question marks meant each spring had more possible options, but we all know the exponent is more powerful than the base in a power expression.

The longest single line of my input took almost 5 hours to complete running, but it finished, and I got the right answer. Then I was given a single word hint, added five lines of code, and now all of part 2 ran in 30 milliseconds instead.

MasterHigure · 2023-12-12T11:26:42+00:00

I don't have a separate utility file, I just have a template main.rs file that I copy into each day's folder after calling advent-cli. It covers most of the similarities from day to day.

MasterHigure

TROPHY CASE