Why is there a puzzle tag? Surely every problem posted on this site is puzzle meaning that it could be applied to everything..
The same applies to the programming-puzzle tag.
It's nowhere near that simple. It depends on other questions which were posted, how similar your question is to recently posted ones, how difficult it appears, how well-written it is, and other even less objective features.
The tag wiki for algorithm consists of a summary:
This challenge is intended to be solved by using, creating, or resolving some processing algorithm.
and a detailed explanation:
This challenge involves algorithms.
At first glance this seems to be about as useful as tagging questions p...
Be an Epidemiologist!
code-challenge
Challenge
You must create a simple model of how disease spreads around a group of people.
Rules and Requirements
The model must be a 1000 by 1000 2D array with each element being a different person.
The user must input two variables: the probability of t...
More than trying to beat each level, he's lately been playing with the arcs trying to get an exact target percentage with each one. It's interesting to watch him experiment.
If you don't need occlusion then you can just draw squares of a fixed size centred on the origin, using a simple projection (if you don't need perspective you could use an isometric projection)
@user First draw the fuselage, then the wings and tail. The level of detail matters; if you need to show individual windows/wheels, it'll be more complex.
do you need depth information? It's simpler to draw them as outlines so those behind are still visible, but that will give ambiguity (optical illusions)
off the top of my head... describe each plane as a great circle on a unit sphere. the surface of the sphere is now covered in 2d shapes. put a point inside (the center?) each shape.
@user2179021 if it's sufficiently generous it may not affect many entrants. I guess you'd need to specify your own machine if you needed to disqualify some
1. Pick a random point. 2. Work out its bounding polygon. (This is the hard bit). 3. For each edge, pick a point just on the other side of the edge. 4. Repeat until you get no new polygons.
Could be improved a bit, but it should in principle run in polynomial time.
Yes, it might be possible to tackle it that way: get the vertices of the graph, work out the edges, from that the faces, and I think you probably have convex faces so picking a point inside each face is fairly simple.
I've got a bit of obfuscated javascript, and I'd like to find out what it does. I could read up on obfuscating in javascript, or I could ask some people who know their stuff.
Where would I post a question like this? It's not a code-golf question per se, but I think it's far more suited to find c...
Hmm. Awesome in a thought-experimenty way I guess. Most of the questions I've looked at seem very vague/broad. I'm also not really sure what I can ask about.
@user2179021 Sandbox it. I can foresee potential issues around numerical analysis (unless you require the planes to have equations which are defined entirely in integers and then expect answers over Q) and around corner cases.
Would the idiot who just posted the deobfuscated malware to meta please edit their post to delete it? I don't want to have to disable my antivirus just to read meta.
@Geobits Yes, I do agree that many of the questions are currently too broad. But I think in principle it's quite nice. And I'm sure they'll settle on more specific questions once they settle into normal operating mode. If you look at early PPCG challenges, we'd consider them quite bad by today's standards.
I wasn't trying to say it was. I meant that it having a positive score and multiple answers indicates that it was accepted well by the community. (not that "bad" questions aren't sometimes also upvoted and answered, but I can't see close votes or vote totals there)
@MartinBüttner I understand that "extrapolate from reality" is being taken to mean "whatever the heck you want to post is fine". That doesn't mean I agree with it.
Or it could fall under the real-world physics section. I don't have personal experience fiddling with quantum mechanics experiments, but others do. Same for magic ;)
@Rainbolt You did read the post though, right? Personal experience is not about personal experience in the concept you're writing about but personal experience in writing about it (i.e., I've used this solution in this and that book/RPG/game before, and it turned out to be well-received/consistent)
Never mind though, I don't even want to start arguing about this. Their site is obviously following some different guidelines than most SE sites, and I don't see why the PPCG chat room should be bothered with that.
@Geobits Well, I'm not sure what those are actually like, but I could see objective questions asked on those... questions about religious writings and history of the religion aren't any different from questions on scifi.SE or history.SE
then again, that's probably also possible with astrology... sadly...
Agreed, but you could say the same about zodiac (I assume there are old texts about it?). I meant that the ones I've seen have a lot of "interpretation" questions.
I've noticed today that some of our badges have names and their description in Portuguese. This isn't affecting SO or WorldBuilding. (Google Translate says that it's Portuguese rather than Spanish. It may be wrong.)
I am not in Spain/Portugal; I am in the United Kingdom and my language is set to...
I've noticed today that some of our badges have names and their description in Portuguese. This isn't affecting SO or WorldBuilding. (Google Translate says that it's Portuguese rather than Spanish. It may be wrong.)
I am not in Spain/Portugal; I am in the United Kingdom and my language is set to...
Draw an Apollonian Gasket
code-golf graphical-output fractal
Given three mutually tangent circles, we can always find two more circles which are tangent to all three of those. These two are called Apollonian circles. Note that one of the Apollonian circles might actually be around the three ini...
@Geobits I saw something about prime numbers on Google and thought "How would searching for prime numbers only affect your game when a golden cookie was clicked?"
Plus my brother is an artist and used GIMP so I thought of that
Surely the transform you need to apply is a rotation which takes wlog (1, 0, 0) to the random point on the surface of the sphere. And you need to apply it to your points as points, not just change the z coordinate.
@PeterTaylor ok so in theory what I am doing is choosing a point at random from the surface of a sphere using the formula at the bottom of mathworld.wolfram.com/SpherePointPicking.html
@PeterTaylor and then attempting to draw the hyperplane orthogonal to that point. And I am doing it wrong :(
The easiest way to get it working is probably to build a mesh grid yourself using two orthogonal vectors in the plane. Getting two orthogonal vectors in the plane is the tricky bit. I can't find the code where I've done this before, so a less optimised approach is to take your normal N; compute the cross products N x (1, 0, 0), N x (0, 1, 0), and N x (0, 0, 1); pick the largest of them and normalise it to get X, and then take N x X to be Y.
I'm not sure why people thought it would be 9 anyway. Windows has a very strange naming history anyway (3, 95, 98, ME, 2000, XP, 7, 8... am I missing anything?). It would be odd for them to stay with something so obvious for too long.
3 was probably the third major release. 95 was probably released in 1995. 98 was probably released in 1998. ME was released around the millenium (I remember that from some high school textbook). XP I have no idea wtf it means. 7 was the seventh popular major release. 8 was the 8th popular major release. Wtf does 10 mean?
And 10 apparently represents that it's a huge jump from 8:
> Windows 10 is such a substantial leap, according to Microsoft's executive VP of operating systems, Terry Myerson, that the company decided it would be best to skip over Windows 9, the widely expected name for the next version.
Which are both terrible reasons IMO.
Let me run this through Amazon's "card checker" and I'll let you know.
Oh... I'm sorry, I don't work well with Mastercard. Do you perhaps have a Visa or American Express?
GPS: Golfed Positioning System code-golf geometry 3d
Your mission, should you choose to accept it, is to write code for a GPS receiver.
Input
The current time, as nanoseconds from the Unix epoch.
Four satellite signals, in the following format:
The time the signal was sent, as nanoseconds fr...
@PeterTaylor I'm not sure the Apollonian gasket is really a simplification, except that it's in 2D. It seems that the GPS question is only asking for the intersection of 4 spheres, whereas the fractal requires you to find out the radii as well, plus the recursion and plotting part.
Based on the research I've been doing (bad! should be cleaning), if you supply an initial set of 4 circles rather than three then you open up some quite different approaches. In particular, circle inversion coupled with Vietà jumping means that you never have to take square roots.
Hm, I have no idea what you're talking about, but it sounds interesting. What would the interpretation of the 4 circles sizes be? That is, how would they be placed relative to each other?
but never having to take square roots would probably still not mean you could actually do it all in rationals, because at least one of the initial radii ratios will be irrational?
@Peter Taylor What do you mean by Vieta jumping? Storing the two roots by their sum and product? I though it was a technique to prove things by infinite descent.
Why is there a puzzle tag? Surely every problem posted on this site is puzzle meaning that it could be applied to everything..
The same applies to the programming-puzzle tag.
The tag wiki for algorithm consists of a summary:
This challenge is intended to be solved by using, creating, or resolving some processing algorithm.
and a detailed explanation:
This challenge involves algorithms.
At first glance this seems to be about as useful as tagging questions p...
Draw an Apollonian Gasket
code-golf graphical-output fractal
Given three mutually tangent circles, we can always find two more circles which are tangent to all three of those. These two are called Apollonian circles. Note that one of the Apollonian circles might actually be around the three ini...
