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What are the lesser known but cool data structures?
- arethuza 15y agoWorking with CouchDB has taught me about append-only btrees, which are quite simple but rather neat: http://www.bzero.se/ldapd/btree.html http://www.bzero.se/ldapd/btree.html
- deleted 15y ago[deleted]
- nickolai 15y agoAlready discussed here : http://news.ycombinator.com/item?id=1370847 http://news.ycombinator.com/item?id=1370847 and I think there was a more recent repost but I cant seem to find it.
- nyellin 15y agoI wish they wouldn't close questions like this.
- LeafStorm 15y agoConsidering that they don't really line up with the goals of a "normal" SO question, I can't really blame them for closing it. It may be better for them to create a separate section for these types of open-ended questions.
- twymer 15y agoI thought they were encouraging such questions to be posted on http://programmers.stackexchange.com/ http://programmers.stackexchange.com/ instead.
- icebraining 15y agoI don't think so, from the FAQ: You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page. Programmers is simply for less focused on code, more conceptual questions.
- vajrabum 15y agoWell then they're missing out. The only time I visit Stack Overflow is when it comes up in a Google search or when it shows up on hacker news with something actually useful and book-markable like this.
- itafroma 15y agoProgrammers mod here: this is inaccurate, as these types of questions are pretty much off-topic everywhere on Stack Exchange. Programmers is the whiteboard to Stack Overflow's compiler: if you have a specific (emphasis on specific) programming issue that doesn't involve code, it's likely on-topic for Programmers. If it's just a poll of weird/funny/cool/etc. stuff, it's not welcome.
- optimisticprog 15y agofacist moderators who delete the site's best questions make it worse one deletion at a time.
- smackfu 15y agoIt's too bad the name is so generic, or that it makes such a fine distinction between programmers and programming.
- itafroma 15y agoI agree it's not intuitive, particularly to those not well-versed in the history of Stack Overflow. For the backstory, when there was just Stack Overflow (and not the network of Stack Exchange sites), there was a large contingent of people who wanted Stack Overflow just for programming problems (and not programmer-related questions, like business concerns, conceptualizing, or lists like these). So the early Stack Overflow population separated everything into "Programming Related" (on-topic) and "Not Programming Related" (off-topic) questions. When Stack Exchange 2.0 launched (allowing people to suggest new sites), one of the sites that launched in the first wave was "Not Programming Related" which was intended to house all the fun stuff that was now off-topic on Stack Overflow. Turns out, having a free-for-all site doesn't work, and the quality was all over the place. So it was retuned into being a site for questions about being a programmer or acting as programmer (so, business or conceptual questions answerable by programmers)—which captured 85-90% of the quality questions on the new site—to Stack Overflow's concrete programming (questions specifically about implementation): hence the name, Programmers.SE.
- pnathan 15y agoNo, Programmers is for strict Q&A as well. I am on record on meta.programmers.se as disagreeing with that policy.
- jroseattle 15y agoSO is quickly approaching reference territory. It is my go-to authority on most programmatic questions. And not all content takes the form of a how-do-i-solve-this-problem format. Would be good to see them re-purpose that good information (like this particular entry) into a useful format.
- chrisaycock 15y ago> Would be good to see them re-purpose that good information (like this particular entry) into a useful format. Like cough Wikipedia? Most of the entries on that page are links to a Wikipedia article with a one-paragraph summary. Seems like anything missing from the canonical list should just be added: http://en.wikipedia.org/wiki/List_of_data_structures http://en.wikipedia.org/wiki/List_of_data_structures
- metellus 15y agoWikipedia is a good place for information about different data structures, but the question here is "What are the lesser known but cool data structures. There are tons of obscure data structures, but only a few that people would consider cool. Wikipedia cannot and should not show that information, because it's inherently subjective.
- anothermachine 15y agoStackOverflow cannot show that information either, because it's inherently subjective! "What are some data structures not found on Wikipedia" is an objective question (but time-bound, which violates an SO policy)
- jroseattle 15y agoWikipedia was my first thought, but it's more encyclopedia oriented (naturally). I was thinking something more along the lines of what they did with Scala: http://stackoverflow.com/tags/scala/info http://stackoverflow.com/tags/scala/info
- Someone 15y ago
- dustingetz 15y agospeculation 1) its a doozey on their database speculation 2) they don't make money on content like this. (um, maybe its significantly less referrers from search?)
- icebraining 15y agoI think that's unfair, the mod who closed it isn't even an SO employee.
- cruise02 15y agoThe SO employees have seen it. If they want questions like this open, they all have the power to override moderators.
- icebraining 15y agoMaybe they simply agree the question doesn't fit the SE model? I'm not saying the company running SO doesn't want it closed, I'm saying it's unfair to assume that's because it's "inconvenient" to them.
- cruise02 15y agoI don't follow you. I'm not assuming it's inconvenient for them. It's very convenient. They just have to click a few buttons to reopen a question like that. I know for a fact that they really don't want them to remain open.
- icebraining 15y agoWe know they don't want it open. The question is why. dustingetz was speculating they don't want it open because it either hits too much on their database or doesn't make enough money from it. My position is that they feel the question doesn't fit with the SE model and there's no ulterior/egotistical reason behind keeping it closed.
- laluser 15y agoSkip lists is such one that I wasn't taught in school. I did not learn about them until a friend brought them up in a conversation. They are probably taught in upper level algorithm courses.
- _delirium 15y agoThere were some interesting additional examples (and commentary) in the HN discussion when this was last linked (18 mos ago): http://news.ycombinator.com/item?id=1370847 http://news.ycombinator.com/item?id=1370847
- diminish 15y agoHey a good startup idea. A Vote based web site for subjects covered in `non constructive Stackoverflow entries`..
- breckinloggins 15y agoI like the part where the most informative, educational, and interesting discussions on StackOverflow are inevitably closed as "Not Constructive".
- cruise02 15y agoStack Overflow isn't a discussion board. It's a Q&A site. It's not intended for neverending lists that don't have a correct answer.
- nyellin 15y agoIs that so? Are the "benefits of initiating followers into the Blades of Skyrim?" more helpful or factually verifiable than a list of lesser known data structures? http://gaming.stackexchange.com/questions/41411/whats-the-benefit-of-initiating-followers-into-the-blades http://gaming.stackexchange.com/questions/41411/whats-the-be...
- cruise02 15y agoThat has 2 answers. The datastructures question got closed after 89 (some of them duplicates). Plus they're on two different sites. I don't get the point of your reference.
- nyellin 15y agoMy point was that I'd appreciate, at the very least, a StackExchange site for this type of question.
- cruise02 15y agoYou can suggest one on Area 51 (http://area51.stackexchange.com/ http://area51.stackexchange.com/) but I doubt it will get much traction. The Stack Exchange engine is much better for objective questions that have a correct answer than subjective questions that have a lot of different answers. Hacker News and reddit are much better for discussion topics.
- itmag 15y agoI'd like to add a similar question: what are the lesser known but cool control structures?
- ebtalley 15y agoAs someone who dabbled in SO I quickly became disillusioned with the site after I posted a question on LaTeX and quickly had it closed and then was shuttled over to the "new" LaTeX site. IMHO, If the question doesn't fit the current policy don't make the submitter waste his time posting the same material on 5 different SO sites in order to get a hit. Find a way to transfer it where the conversation can continue to flourish.
- phwd 15y agoI don't seem to understand what you are saying. Answers and comments are transferred when a question is migrated. In all cases where users have a problem it is best to raise your issue on meta.stackoverflow.com or at least reference the question you are talking about above.
- nulluser 15y agoMost LaTeX question are not programming questions, so they get shipped over to the TeX site. You'll likely get a better answer there than on SO (that's the whole point of creating all these sites). And as phwd said, all the content (answers and comments) also get moved.
- cruise02 15y ago> Find a way to transfer it where the conversation can continue to flourish. That's exactly what happened. 99% of questions get answered on the LaTeX site. It's one of the best communities in the SE network. Compare that to only about 90% of questions tagged 'latex' getting answered on Stack Overflow. Not bad, but still better to migrate them to an active site dedicated to the topic.
- ww520 15y agoLess known data structures come to mind: - Topological sort. Great for dependency traversal. - KD-Tree. Great for geo-spatial search. - Consistent Hashing. Great for scaling and clustering. - Fuzzy Hashing. Great for document digest and mining. Sadly there might be a patent conflict somewhere. - Extendible Hashtable. Amazing space-efficient and extendible lookup table. - Bloom Filter. Space-efficient check.
- tptacek 15y agoA favorite answer to this (recurring) question: aguri trees. I've written about them before: http://hackerne.ws/item?id=101969 http://hackerne.ws/item?id=101969 (the blog post is dead, but you can find some of it at bit.ly/tN2ESX) For data sets with binary keys in which prefixes are meaningful (most notably: IP addresses, but also memory addresses and probably many integer keys that have natural range semantics), Aguri is a radix trie implementation that exploits tree structure to infer ranges in the data.
- spearo77 15y agoFar more courteous disagreement back in the day ;)