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Thread Rules
1. This is not a "do my homework for me" thread. If you have specific questions, ask, but don't post an assignment or homework problem and expect an exact solution.
2. No recruiting for your cockamamie projects (you won't replace facebook with 3 dudes you found on the internet and $20)
3. If you can't articulate why a language is bad, don't start slinging shit about it. Just remember that nothing is worse than making CSS IE6 compatible.
4. Use [code] tags to format code blocks. |
On September 12 2016 13:05 Birdie wrote:I haven't done much with userscripts before but pretty sure they have easy access to the DOM, so you just need to find how posts are stored in the DOM and then find the element with the username you want to hide, then remove it. IDK if that's enough to go off or you need more specifics though. E.g.
<tr id="post-8073303">
<td class="c_username">
<a href='http://s9.zetaboards.com/Ultimate3D_community/profile/44616/' class='member'>AZARKON THE GREAT</a><a name='post8073303'></a>
</td>
So you just navigate the DOM for anything with id = post-SOMETHING, then within its children, check class=member, check the text for the usernames you want to hide, and if so use whatever DOM manipulation userscripts have to hide/remove the whole post tr.
alright thats helpful.
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Have any of you used the new google cloud speech api or worked with media file conversions?
I'm getting some strange error from them that I don't really know how to approach:
Invalid FLAC header: incorrect FLAC marker
The recording is captured from the mic via JS and saved as a .wav file. It is then converted to .flac with sox, base64 encoded and sent to google api as per their docs. Googling this error isn't helpful...
Edit: file info before and after coversion
kkarski@debian:~ $ avprobe 009.wav
avprobe version 11.7-6:11.7-1~deb8u1, Copyright (c) 2007-2016 the Libav developers
built on Jun 12 2016 21:51:35 with gcc 4.9.2 (Debian 4.9.2-10)
Input #0, wav, from '009.wav':
Duration: 00:00:04.50, bitrate: 256 kb/s
Stream #0.0: Audio: pcm_s16le, 16000 Hz, 1 channels, s16, 256 kb/s
# avprobe output
kkarski@debian:~ $ avprobe 009.flac
avprobe version 11.7-6:11.7-1~deb8u1, Copyright (c) 2007-2016 the Libav developers
built on Jun 12 2016 21:51:35 with gcc 4.9.2 (Debian 4.9.2-10)
Input #0, flac, from '009.flac':
Metadata:
COMMENT : Processed by SoX
Duration: 00:00:04.50, bitrate: 99 kb/s
Stream #0.0: Audio: flac, 16000 Hz, mono, s16
# avprobe output
Edit2:
Nevermind. I checked some of the sample code on the google cloud platform and the docs are most likely outdated. Sending them .wav denoted as LINEAR16 encoding worked on first try...
Fucking hate such dumb things.
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let's saying im looping through an arraylist
checking for a certain result based on user input within it's elements
and when I am done, I want to change some of the indexes to something that I know *for sure* will not be what the user is searching for
is there a way to set indexes as "empty"? Is the only option to make those indexes null? meaning that I will have to account for that in my code? Or is there something easier than null.
Say, the indexes will have strings. Is there an option for a valueless string, or is null the best I can do?
(in java)
edit: epiphany. can I do "" ?
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On September 14 2016 06:53 travis wrote:
let's saying im looping through an arraylist
checking for a certain result based on user input within it's elements
and when I am done, I want to change some of the indexes to something that I know *for sure* will not be what the user is searching for
is there a way to set indexes as "empty"? Is the only option to make those indexes null? meaning that I will have to account for that in my code? Or is there something easier than null.
Say, the indexes will have strings. Is there an option for a valueless string, or is null the best I can do?
(in java)
edit: epiphany. can I do "" ?
Indexes are integers, and thus cannot be set equal to "". You could clearly set it to -1 (a very usual way of initializing an int before looping through an array and setting it to something useful). You then test after the loop whether it is still -1, and treat this exceptional situation. You could also use the value directly, rather than the index. This can be initialized as null (or set to null when you find nonsense). Just remember that operations on null objects throws null pointer exceptions. And trying to find the -1th element in a list throws an array index out of bounds exception. So always remember to check your corner cases.
Oh, and null is pretty easy. It also has the advantage of failing immediately if you don't treat it properly, rather than letting your code Gail at some completely unrelated spot. Debugging this becomes: "why is this null", rather than "what the fuck happened?" 
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sorry I didn't say what I mean accurately. I don't mean to change the index. I mean to change the value of the given index (the string) to something that the user wouldn't possibly be searching for.
I don't want to lose the index itself, or else I would just remove it from my arraylist.
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On September 14 2016 07:10 travis wrote:
sorry I didn't say what I mean accurately. I don't mean to change the index. I mean to change the value of the given index (the string) to something that the user wouldn't possibly be searching for.
I don't want to lose the index itself, or else I would just remove it from my arraylist.
You mean you want to change array value at a given index (not value of the index). Nothing simpler...
if (arrList.contains("search string")) {
arrList.set(arrList.indexOf("search string"), "won't find it again!");
}
/*
can just set it to null if you want to, but this might break things since both
contains and indexOf need an object of some sort as their argument
*/
My java is clunky. Someone please confirm...
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there will be multiple search terms, and I don't know what they are, so I can't set it to another string
I know I can set it to null, I was just wondering if there was a better option - is empty string a thing?
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Why can't you just remove the objects from the list if you know you don't need them?
On September 12 2016 13:25 WarSame wrote:Show nested quote +On September 12 2016 06:52 Blisse wrote:
Yeah, academic integrity policy is intentionally vague so that it's a lot easier on them when they provide proof. Generally it's fine as long as you're just talking about the solution and not given exact pseudo/code. All reasonable professors I've seen encourage discussion, just not discussion with code being written.
I've consulted TL for a bunch of things too.
Instead of giving the problem description, you should abstract it one step up. I know it's a bit harder to do since you're starting out, but asking, "how do you find the smallest range of numbers in a list that contains a given set of numbers?" gives essentially the same solutions, and as long as no one is writing out a program for you, it should be fine asking for help.
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Actually it's kind of annoying/interesting that a lot of programming questions essentially rely on tricks that you need to learn first before you can actually solve them. Using sets and dictionaries IMO don't come intuitively, but instead from me reading advice that they're generally how to best solve a problem, and then I base my thinking with that in mind. I think the extreme example is being asked to find a loop in a linked list. No way you can reason yourself to a solution. I mean, I'm not particularly good, but couldn't you just put the pointer values of each node in a dict when visited, and if you come to a node already in the dict, then you've got a loop?
How would you approach the problem if you couldn't hash the objects because the list is huge?
+ Show Spoiler [hint] +
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On September 14 2016 11:15 Blisse wrote:Why can't you just remove the objects from the list if you know you don't need them? Show nested quote +On September 12 2016 13:25 WarSame wrote:On September 12 2016 06:52 Blisse wrote:
Yeah, academic integrity policy is intentionally vague so that it's a lot easier on them when they provide proof. Generally it's fine as long as you're just talking about the solution and not given exact pseudo/code. All reasonable professors I've seen encourage discussion, just not discussion with code being written.
I've consulted TL for a bunch of things too.
Instead of giving the problem description, you should abstract it one step up. I know it's a bit harder to do since you're starting out, but asking, "how do you find the smallest range of numbers in a list that contains a given set of numbers?" gives essentially the same solutions, and as long as no one is writing out a program for you, it should be fine asking for help.
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Actually it's kind of annoying/interesting that a lot of programming questions essentially rely on tricks that you need to learn first before you can actually solve them. Using sets and dictionaries IMO don't come intuitively, but instead from me reading advice that they're generally how to best solve a problem, and then I base my thinking with that in mind. I think the extreme example is being asked to find a loop in a linked list. No way you can reason yourself to a solution. I mean, I'm not particularly good, but couldn't you just put the pointer values of each node in a dict when visited, and if you come to a node already in the dict, then you've got a loop? How would you approach the problem if you couldn't hash the objects because the list is huge? + Show Spoiler [hint] +
That's pretty dirty. I'm interviewing people on Friday and gonna use that one thanks. I think it's a good demonstration that it is really easy to a solution, but thinking through for the best one requires a person to be on another level entirely.
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afaik it's not too obscure, so people might have heard of it. I think I remember seeing it in a small lab assignment in my lower data structures/algorithms class a couple years ago.
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Yeah I had an assignment on that in uni year two or so I think.
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I agree the list cycle one is somewhat of a known question...some variants are 1) determine first node of the cycle; 2) determine the length of a cycle. One fun question I heard lately was:
> There are N buildings with variable number of floors, and we want to build additional floors so that at least m buildings are of the same height. Minimize the cost of building the floors.
Best solution I could arrive at was NlogN (where N is number of buildings, m is the number of buildings you're trying to raise to same height).
Cloudflare DNS outage @ my location right now and 1/2 the internet down t_t (including programmerinterviewer somehow so excuse me if they mentioned both those subproblems on the site)
On September 14 2016 06:53 travis wrote:
let's saying im looping through an arraylist
checking for a certain result based on user input within it's elements
and when I am done, I want to change some of the indexes to something that I know *for sure* will not be what the user is searching for
is there a way to set indexes as "empty"? Is the only option to make those indexes null? meaning that I will have to account for that in my code? Or is there something easier than null.
Say, the indexes will have strings. Is there an option for a valueless string, or is null the best I can do?
(in java)
edit: epiphany. can I do "" ?
Imo it'd be helpful if you gave a little context about what problem you're trying to solve. For example sure you can use null (well in Java you can't use null if you're using a primitive typed array but w/e), but another approach might be maintain a set of the previously guessed indicies and check that per iteration. I can't think of a not artificial case where you'd want behavior like this...maybe you're trying to shuffle?
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On September 14 2016 11:15 Blisse wrote:Why can't you just remove the objects from the list if you know you don't need them? Show nested quote +On September 12 2016 13:25 WarSame wrote:On September 12 2016 06:52 Blisse wrote:
Yeah, academic integrity policy is intentionally vague so that it's a lot easier on them when they provide proof. Generally it's fine as long as you're just talking about the solution and not given exact pseudo/code. All reasonable professors I've seen encourage discussion, just not discussion with code being written.
I've consulted TL for a bunch of things too.
Instead of giving the problem description, you should abstract it one step up. I know it's a bit harder to do since you're starting out, but asking, "how do you find the smallest range of numbers in a list that contains a given set of numbers?" gives essentially the same solutions, and as long as no one is writing out a program for you, it should be fine asking for help.
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Actually it's kind of annoying/interesting that a lot of programming questions essentially rely on tricks that you need to learn first before you can actually solve them. Using sets and dictionaries IMO don't come intuitively, but instead from me reading advice that they're generally how to best solve a problem, and then I base my thinking with that in mind. I think the extreme example is being asked to find a loop in a linked list. No way you can reason yourself to a solution. I mean, I'm not particularly good, but couldn't you just put the pointer values of each node in a dict when visited, and if you come to a node already in the dict, then you've got a loop? How would you approach the problem if you couldn't hash the objects because the list is huge? + Show Spoiler [hint] +
Pointers are tiny, so even a list with a million entries will have pretty much insignificant memory impact compared to the list and data itself, so a simple dictionary solution would still be pretty easy and probably faster, too, since you can abort on the first duplicate node. With the tortoise and hare solution you have to cross the distance that the slower pointer completed already, which means in a completely circular list you pretty much have to check 1.5n elements. The slower pointer crosses half the distance in the time for one complete loop, so now the faster pointer has to move around again until it reaches the slower pointer which is half the loop ahead. You can increase the speed at which the faster pointer moves, but then you'll be slower for partial loops that the faster pointer will circle around multiple times before the slower even enters them.
In any case, the situation is completely academic since you should never have to check in code whether a list is circular or not. You should never actually interact with the nodes directly, only the data they contain, which means that you couldn't even be able to create any loops in a non-circular list if you wanted to. If you create your own linked list implementation then your code shouldn't allow for the possibility of a loop when you don't want one and making such a potentially expensive check at runtime inside a library is generally a bad idea.
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Wee! I went over 100 rep on SO. I don't know why but it feels awesome 
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On September 14 2016 19:55 Manit0u wrote:Wee! I went over 100 rep on SO. I don't know why but it feels awesome
My account has a bit more, but I have no idea how to access it now, because it was registered with openid years ago and that is no longer available to log in. I stopped actively using the site now anyways. The noise-to-signal ratio is constantly increasing on that site.
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Russian Federation4235 Posts
On September 14 2016 17:34 Morfildur wrote:Show nested quote +On September 14 2016 11:15 Blisse wrote:Why can't you just remove the objects from the list if you know you don't need them? On September 12 2016 13:25 WarSame wrote:On September 12 2016 06:52 Blisse wrote:
Yeah, academic integrity policy is intentionally vague so that it's a lot easier on them when they provide proof. Generally it's fine as long as you're just talking about the solution and not given exact pseudo/code. All reasonable professors I've seen encourage discussion, just not discussion with code being written.
I've consulted TL for a bunch of things too.
Instead of giving the problem description, you should abstract it one step up. I know it's a bit harder to do since you're starting out, but asking, "how do you find the smallest range of numbers in a list that contains a given set of numbers?" gives essentially the same solutions, and as long as no one is writing out a program for you, it should be fine asking for help.
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Actually it's kind of annoying/interesting that a lot of programming questions essentially rely on tricks that you need to learn first before you can actually solve them. Using sets and dictionaries IMO don't come intuitively, but instead from me reading advice that they're generally how to best solve a problem, and then I base my thinking with that in mind. I think the extreme example is being asked to find a loop in a linked list. No way you can reason yourself to a solution. I mean, I'm not particularly good, but couldn't you just put the pointer values of each node in a dict when visited, and if you come to a node already in the dict, then you've got a loop? How would you approach the problem if you couldn't hash the objects because the list is huge? + Show Spoiler [hint] + Pointers are tiny, so even a list with a million entries will have pretty much insignificant memory impact compared to the list and data itself, so a simple dictionary solution would still be pretty easy and probably faster, too, since you can abort on the first duplicate node. With the tortoise and hare solution you have to cross the distance that the slower pointer completed already, which means in a completely circular list you pretty much have to check 1.5n elements. The slower pointer crosses half the distance in the time for one complete loop, so now the faster pointer has to move around again until it reaches the slower pointer which is half the loop ahead. You can increase the speed at which the faster pointer moves, but then you'll be slower for partial loops that the faster pointer will circle around multiple times before the slower even enters them. In any case, the situation is completely academic since you should never have to check in code whether a list is circular or not. You should never actually interact with the nodes directly, only the data they contain, which means that you couldn't even be able to create any loops in a non-circular list if you wanted to. If you create your own linked list implementation then your code shouldn't allow for the possibility of a loop when you don't want one and making such a potentially expensive check at runtime inside a library is generally a bad idea.
On a typical 64-bit machine, for a list of integers, the "next" pointer is 2/3 of each node's size, so you will have a data structure that will be comparable in size to the list itself. Besides, typical implementations of the map data type have additional bookkeeping costs. For the worst case of the loop, in the "pointer hop" solution you're expected to make 3n pointer dereferences (n for the slow pointer and 2n for the fast), I believe. Using an unordered_set, that will turn into n hops for the scan, at least 2n for lookups and insertions (assuming bucket-based hash table with NO collisions at all) and 2n calculations of the hash function and n copies of the pointers. So that's { 3n operator*(ptr) } vs { 3n operator*(ptr) + 2n hash(ptr) + n copy(ptr) } which is already not in favor of the hash-based solution, and that is assuming everything is inlined, otherwise you will have function calls which will make the two non-comparable, really.
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On September 14 2016 16:41 Aerisky wrote:
afaik it's not too obscure, so people might have heard of it. I think I remember seeing it in a small lab assignment in my lower data structures/algorithms class a couple years ago.
Our current interview question is FizzBuzz so I doubt its more known than that if nothing else. If anyone has better suggestions we're overhauling the process because it sucks.
The position/skill level that I interview for is the interns and new graduate devs.
On September 14 2016 17:34 Morfildur wrote:
In any case, the situation is completely academic since you should never have to check in code whether a list is circular or not. You should never actually interact with the nodes directly, only the data they contain, which means that you couldn't even be able to create any loops in a non-circular list if you wanted to. If you create your own linked list implementation then your code shouldn't allow for the possibility of a loop when you don't want one and making such a potentially expensive check at runtime inside a library is generally a bad idea.
While this is true; I wouldn't expect any of the people I'm hiring to write an algorithm anyway. It's mostly about listening to them think through a solution and it has enough right answers that I'd expect them to get one of them even if it isn't the optimal one. If said person can explain the limitations of their answer then I'll be happy with their solution.
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On September 14 2016 07:40 travis wrote:
there will be multiple search terms, and I don't know what they are, so I can't set it to another string
I know I can set it to null, I was just wondering if there was a better option - is empty string a thing?
Seems likhe that question still was not answered, or I missed it.
Yes, empty string is a thing. Perfectly normal. And certainly not something you should accept as a search term by the user.
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EPT
