### MikeMirzayanov's blog

By MikeMirzayanov, history, 3 years ago, translation, ,

Hi everybody!

First, I invite you to take part in an official Testing Round #12. The fact is, the Codeforces team has made numerous changes to the platform (details are below), and we want to be sure that the basic functionality remained unchanged. This round will have a shortened duration of 1.5 hours, consist of 3 (maybe 4) problems that you might have already seen before. Its purpose is to test the system on the one hand, and on the other hand — to brighten up a Wednesday evening. Of course, the round will be unrated.

Now the main thing. This coming Friday (yes, the 13th of November) Codeforces starts another line of rounds. We called them Educational Rounds. Using my students at the Saratov State University Programmings Competitions Training Center as an example, I regularly notice that even those who have a considerable progress in the results on the rounds often have narrow purview in terms of standard topics and ideas, they are not familiar with many well-known problems and methods. The fact is, the rounds often avoid any folk or classical subjects, thus underdeveloping the purview of young generation of the participants.

We are pleased to announce the start of a series of educational rounds! They will take place with the regularity of a round 2-4 times per month.

Their characteristics are like that:

• The duration is classic — 1.5 — 2.5 hours;
• The goal is rather to practice and to educate, than to compete;
• Not only problems, but also exercises can be used;
• Useful, even well-known ideas will be reused in order to introduce them to a wide range of participants;
• Often the formal text of the statements;
• Unrated (perhaps for now);
• We will try to conduct them in the ACM-ICPC mode (if there are long waiting lists, we may change the approach);
• The results that are obtained after the end of the round, are preliminary;
• After the end of the round will be a 24-hour period of open hacks — any visitor of Codeforces may try to hack any complete solution to a problem of the last round (either from a contest, or from practice), the source code of hacking solution is available (you can copy the text and, for example, stress it);
• All successful hacks from the previous item will be added to the official test set and after as long as 24 hours after the end of the round retesting of all complete solutions will be made;
• Only after the final standings based on improved test data, the results are final;
• The results of a round are calculated separately by division;
• Our ability to process such problems are limited, so actually the test suites from the jury are expected to end up incomplete — we are looking forward to your hacks!

Basically, we will be oriented towards the members of the second division, but often these rounds will be of interest to more experienced participants.

For now preparing problems to these rounds will be concentrated at the Saratov State University Programming Competitions Training Center, most of the work with the problems will be accomplished by Edvard homo_sapiens Davtyan. We wish him good luck, enthusiasm and energy!

See you at the Testing Round #12, and later at the Educational Codeforces Round 1.

•
• +1052
•

 » 3 years ago, # | ← Rev. 2 →   +11 excited! it may be Educational Hackforces Round 1, very very interesting.
•  » » 3 years ago, # ^ |   0 Hello!everyone.tourist have come back! and I will be legendary grandmaster in several contests!
•  » » » 3 years ago, # ^ |   +13 But you must be a cheater!!
•  » » » » 3 years ago, # ^ |   +3 How can he cheat during a contest ? sorrytourist, We will see what you can do
•  » » » » » 3 years ago, # ^ |   0 He isn't tourist.you can see his school UESTC.that is a chiese school.
•  » » » 3 years ago, # ^ |   0 hello! tourist! -_-
•  » » 3 years ago, # ^ |   +17 where is the problem?
•  » » » 3 years ago, # ^ |   0 I also would like to know/
 » 3 years ago, # |   +3 Since I'm going to hold a codeforces mashups for my students this Saturday, I wonder whether Gym/Mashups will work normally during the 24-hour period of open hacks. Thank you.
•  » » 3 years ago, # ^ |   +11 Yes
•  » » » 3 years ago, # ^ |   0 Thanks. It will be helpful for new programmer.
 » 3 years ago, # |   0 No rating change for a while then :( Keep it up tho!
 » 3 years ago, # |   0 This is an excellent idea! It will fill gap between classical books like CLRS and problems on rated contests.
 » 3 years ago, # | ← Rev. 2 →   -93 how much time does a 5*1000000000 loop take on codeforces?
•  » » 3 years ago, # ^ |   -9 Not the right place for a question like that.
 » 3 years ago, # | ← Rev. 2 →   0 Dose the Educational Codeforces Rounds have a different styles in It's tutorials or the as same as the regular ones MikeMirzayanov ?
 » 3 years ago, # |   +4 I am very looking forward to the coming contest ! :-)
 » 3 years ago, # |   +59 The Educational Rounds seems a great idea. I suggest introducing a separate rating for the Educational rounds, this will act as an incentive for contestants to participate more actively in them..
•  » » 3 years ago, # ^ |   -15 I think, everyone, who really wants to increase their knowledge will take a part in educational rounds without any additional points. People, who write contests here only to make their rating higher are not welcome (by me). In my honest opinion.
•  » » » 3 years ago, # ^ |   +19 Rating is Motivation :)
•  » » » 3 years ago, # ^ | ← Rev. 2 →   0 How create contest? I am look forward to increase rating sir
 » 3 years ago, # | ← Rev. 2 →   +6 How will the Educational Codeforces Round be beneficial to the Div 2 participants ? what are the differences between Div 2 and Education Codeforces Round ?
 » 3 years ago, # |   +9 I think I'm gonna love Codeforces more and more ! Gooood Job !
 » 3 years ago, # |   0 thanks for this opportunity codeforces :p
 » 3 years ago, # |   0 Interesting :D
 » 3 years ago, # |   0 Great , just i wish u make it rated (Educational rounds)
 » 3 years ago, # |   +6 This is great! Most of my knowledge in algorithm/competitive programming comes from CodeForces, and it's great, but I sometimes don't know super basic stuff... (For example, at some point, I think I had way more experience in segment tree than dynamic programming... xD.)
 » 3 years ago, # |   +4 (unrated) excited !! :D great thinking mike ! :)
 » 3 years ago, # |   +133 Thumbs up if you learned the word "purview" from this post :)
•  » » 3 years ago, # ^ |   +32 I was too lazy to read the whole post, so I learned it from you. :D
•  » » 15 months ago, # ^ |   0 Read the russian version of this post, learned the word from you (:
 » 3 years ago, # |   +19 Thank you Codeforces team :) It's a great idea.That's why Codeforces is always one step ahead than other contest sites :) But i think separate rating system for the educational round should be introduced.It will surely increase the number of participants!
 » 3 years ago, # |   0 Thank you very much.
 » 3 years ago, # | ← Rev. 2 →   0 It is Very Good Idea :) But Please & Please... Good Translation :D Thanks
 » 3 years ago, # | ← Rev. 3 →   +66 It is a very great idea. I often notice that my skills are honed into participation in Codeforces and Topcoder contests. That does not really mean that I am good at algorithms. While speaking with guys who specialize in knowing theory behind various algorithms, I often come to conclusion that my knowledge is very limited. Another side is the fact that my skills are not very useful at production. While at contests I often use hashing or treaps, it is a horrible idea to use them behind real-time system, given there are better alternatives. I suggest making these educational rounds in such a way, that encourages contestants to use different approaches to the same problems. For example, you can make three different tasks: "Strstr Hashing", "Strstr KMP", "Strstr BM". Then add a line into statement: "This problem should be solved by using KMP algorithm. While you can technically solve it using different algorithm, the purpose of this round is education, and cheating negates your educational progress". I suppose that will work as well as our "Virtual participation" function, and it will only work if the round is unrated.I am looking forward for participating in these rounds.
•  » » 3 years ago, # ^ |   +8 I suggest making these educational rounds in such a way, that encourages contestants to use different approaches to the same problems. For example, you can make three different tasks: "Strstr Hashing", "Strstr KMP", "Strstr BM". Then add a line into statement: "This problem should be solved by using KMP algorithm. While you can technically solve it using different algorithm, the purpose of this round is education, and cheating negates your educational progress". The trick "let's think about one problem in different ways" is quite useful because sometimes it gives notable time savings in explanations, sometimes it makes this explanations spectacular — all in case when problem is easy enough, and mb in some other cases. But noone should use it as a reason to memorize the implementations of three different algorithms to get AC . It's the only possible reaction to "should be solved by KMP" for most part of users, I know it by my own observations during last years (and personal experience, of course).The idea that "the problem should require competence NAME to be useful in learning process" is not bad by itself, especially because the only one well-known and undeniable method of learning to code specific algorithm in contest is actually doing it. But it is also known that problem must show the importance of algorithm (or it's basic ideas) and related topics of math and physics in natural or at least non-artificial way [Arnold] .This words may seem senseless and empty until you start to think what's the target of competitive programming instead of thinking about problems it poses in regular rounds)) Such thoughts made me to write a small blogpost about CF educational rounds, but it's not yet ready to be posted. Let's say more about what is called "natural way". It's ok when you define determinant by 3x3 case as "oriented geometric volume created by three 3d vectors" because there is no way to invent determinant from scratch and it's possible to understand what's the motivation of volume sign, what's the meaning of value and how parallelepiped looks. But you shouldn't define DFS as "this recursive function that can be simply coded to traverse given graph", first of all you should say about several important problems that can be represented as problems about graph structure, you should show how this graps looks and how those problems becomes amazingly simpler when you classify edges by DFS traversal strategy [Sedgewick] . Let's continue about "natural" learning of STRSTR. As for me — the only more or less "ok" way today is to learn string algorithms from [Gusfield] and several other sources during long evenings of this cold winter. It's terribly difficult from time to time or even impossible in case you are not ready for such difficulty level or for such "type of activity". I don't know about any simple and purely creatively-technical option to learn STRSTR algorithms in natural way. The question "how to train contestants with sensibly less effort from their side?" became simpler when I've started to think about automated system for this. But it produces many problems which I consider unsolvable with current techniques that online judges use, for example: How to overcome "memorizing problem" mentioned above? The usage of "hashing + map/set" or "hashmap/hashset" can become mandatory in "STRSTR HASHING" with some modifications so the problem won't be solvable by memorizing classical implementation. But it's not a natural reason to learn hashing, efficient data structures, or string algorithms. How to avoid phrase "solve it by METHOD_NAME"? You can set extra-small ML and anti-hash for "STRSTR KMP/BM" to disallow suffix automata and Rabin-Karp so you don't even need to add line "don't use them" in statement. But it's not a natural reason to learn KMP/BM and methods of effective memory usage.
 » 3 years ago, # |   +3 Great idea, the more CF rounds of any kind the happier I am.
 » 3 years ago, # |   +22 Will be there any pre-declared topics? If it is, then we will be able to learn them before the round and test our skill during the round. It would help us to learn those topics better. Another request as they are Educational round please make the editorial more details not only hints.:D
 » 3 years ago, # |   0 Maybe you could add a rating for this Educational rounds, it would be more fun and competitive, so that every user has two ratings, Educational rating and Rounds rating???
 » 3 years ago, # |   0 will we need to register for these rounds? if yes, how? if no, then can just anyone participate in these while they are in progress?
 » 3 years ago, # |   0 It will be helpful for new programmer. Thanks.
 » 3 years ago, # |   +6 Is it on the same lines as Code Monk on HackerEarth? Btw, I found codemonk really enjoyable with the problem that the difficulty curve of the problems was really too steep for an educational contest.I hope you guys take care of it here at CF. Cheers! :)
•  » » 3 years ago, # ^ |   0 Yeah, the last problem in the set is usually very tough.
 » 3 years ago, # |   +7 Codeforces is becoming the one stop destination for competitive coders (y) .
 » 3 years ago, # |   +42 No problems in the test contest.
•  » » 3 years ago, # ^ |   +2 What's going on? Is this a joke?
•  » » 3 years ago, # ^ |   +11 Glad to hear it works.
 » 3 years ago, # |   +42 It would be nice to give problems :)
 » 3 years ago, # |   +19 I can't see any problems in the test round.
 » 3 years ago, # | ← Rev. 2 →   +24 cant see any problem? Celebrate Diwali folks! Happy Diwali :D
 » 3 years ago, # |   +22 no problem
•  » » 3 years ago, # ^ |   0 You not have enough problems in your life? :D
•  » » » 3 years ago, # ^ |   +8 no there's no problem with this contest :D sarcasm
 » 3 years ago, # |   +18 Problems are not visible to me :(
 » 3 years ago, # |   +23 I cant see any problems！
•  » » 3 years ago, # ^ |   -42 I solved E yee :)
•  » » » 3 years ago, # ^ |   0 where are problems?HAHA
•  » » » 3 years ago, # ^ |   0 i solved the problem set so quickly that i don't even remember, how i did it.
•  » » » 3 years ago, # ^ |   0 Really?
•  » » 3 years ago, # ^ |   +21 The problem setter is John Cena.
•  » » 3 years ago, # ^ |   0 Because u r a single dog.
 » 3 years ago, # |   +1 No problem statement. Am I the only one?
•  » » 3 years ago, # ^ |   0 same here
•  » » » 3 years ago, # ^ |   0 I was doing my assignment -_- . I left it for "THIS" ?? really? -_- :3
 » 3 years ago, # |   +5 Are you kidding with us ?
 » 3 years ago, # |   +14 Are we being tested?
 » 3 years ago, # |   0 I hope there will not be a 15 minutes delay.
 » 3 years ago, # |   +9 we have to guess the problems ?!
 » 3 years ago, # |   0 Guys where the problems are? I can't see them. Only empty list. Issue only with me?
 » 3 years ago, # |   0 Seems that I'm not alone...
 » 3 years ago, # |   +5 problems are hard enough to be invisible. :D
 » 3 years ago, # |   +18 Testing round : it tests our patience!
 » 3 years ago, # | ← Rev. 2 →   +5 we learnt that Testing round has no problem.
 » 3 years ago, # |   0 where are the problems?
•  » » 3 years ago, # ^ |   +14 testing round is tests our patient :)
 » 3 years ago, # |   0 Works fine, I'm happy
 » 3 years ago, # |   +12 the problems are very easy
 » 3 years ago, # |   0 the tasks were too easy for us :))
 » 3 years ago, # |   +50 When you first see the contest with no problems :D
 » 3 years ago, # |   +9 it seems that the basic functionality didn't remain unchanged :D
 » 3 years ago, # |   +2 No Problem!!
 » 3 years ago, # |   +9 So the round is to test how the system behaves if there are no problems in an active contest.
 » 3 years ago, # |   0 where the problems are?
 » 3 years ago, # |   +11 Yes, MikeMirzayanov and GlebsHP aren't online :D
•  » » 3 years ago, # ^ |   +10 homo_sapiens isn't online too :)
 » 3 years ago, # |   +4 the problems level is too tough that they haven't even kept it in problem set
 » 3 years ago, # |   +6 Are u testing our patience? -_-
 » 3 years ago, # |   +5 Time is going on,but problem is waiting.
•  » » 3 years ago, # ^ |   +6 problem is coming by walking. so it is being late :)
•  » » » 3 years ago, # ^ |   0 when everyone go offine,then it will reach.
 » 3 years ago, # |   +6 Please, brighten up a Wednesday evening a little more :)
 » 3 years ago, # |   +3 I'm registered in the Testing Round but I can't see any problem (I mean problem statement for solving). Is there any? Is this normal?
•  » » 3 years ago, # ^ |   +38 Have you tried turning it off and on again?
•  » » » 3 years ago, # ^ |   +12 Yes, several times, but it didn't work :(. I'll try formatting the laptop.Thanks for the advice!
 » 3 years ago, # |   +30 First time to solve all problems in a contest :D
•  » » 3 years ago, # ^ |   +22 First time there's noone ahead of me after 10 minutes.
 » 3 years ago, # |   +1 it seems that I have to study for tomorrow's exam instead of solving blank problems!!
 » 3 years ago, # |   +13 Just hack!!!
 » 3 years ago, # | ← Rev. 2 →   +3 the new round is too hard to see problem
 » 3 years ago, # |   +3 like you make your own destiny , you should make your own problems :v :D
•  » » 3 years ago, # ^ |   0 that's why it is called testing round .
 » 3 years ago, # |   +3 where is the problems in testing roung now?did i miss something?
 » 3 years ago, # |   0 Maybe wrong contest time? :D
 » 3 years ago, # |   +1 Can you make this round rated? So everyone will be 1st and earn a lot of ratings.
•  » » 3 years ago, # ^ |   0 If everyone is first then noone is first.
•  » » » 3 years ago, # ^ |   +3 If everyone is first then noone is second.
 » 3 years ago, # | ← Rev. 2 →   +18 It seems that reading all those comments above is more fun than contest itself :)
 » 3 years ago, # |   +4 I want sleeping..........
•  » » 3 years ago, # ^ |   +3 hahahaha
•  » » 3 years ago, # ^ |   +3 where you are?
•  » » » 3 years ago, # ^ | ← Rev. 2 →   0 I'm in ACfun..
•  » » » » 3 years ago, # ^ |   +4 66666666666
•  » » 3 years ago, # ^ |   +3 orz toilet god！！！
 » 3 years ago, # |   +3 Wow!!! What a problem set....nice!!!
 » 3 years ago, # |   0 I told my teammates(he came back just now) that in the new testing contest,if you solve a problem,it will disappear,and now I have solved all the problems!So you can't see them.→_→
 » 3 years ago, # |   0 the problem is not the problem,the problem is your attitude about the problem !
 » 3 years ago, # |   +1 I want say :6666666666
 » 3 years ago, # |   0 I'm tired of waiting you lost one participant, good luck for others with contest
•  » » 3 years ago, # ^ |   0 contest has postponed :D
 » 3 years ago, # | ← Rev. 3 →   +7 after seen there isn't any problem :(
 » 3 years ago, # |   0 Where are all the questions?
 » 3 years ago, # | ← Rev. 4 →   +7 Oh, come on guys, it's OK that there's no statements. This round is held to see if there would be any bugs or problems. Well, it seems, there they are :)
 » 3 years ago, # |   +6 +100 for successful hacking attempt of codeforces!
 » 3 years ago, # |   +3 Keep calm guys.. it's just an error :)
 » 3 years ago, # |   0 please tell me where are the problems. Am I the only one who can not see the problems?
•  » » 3 years ago, # ^ |   +13 you're not alone
•  » » » 3 years ago, # ^ |   0 I set my mind at rest after I saw the comments... wow,the pictures above are so funny...
 » 3 years ago, # |   0 Sorry, we need to move the round forward for 3 hours.
•  » » 3 years ago, # ^ |   0 What is the exact time??
•  » » » 3 years ago, # ^ |   +2
•  » » 3 years ago, # ^ |   0 come on! It will be too late :(
•  » » 3 years ago, # ^ |   0 sorry, we have to sleep...
 » 3 years ago, # |   0 Well, time to go sleep.
 » 3 years ago, # |   +24 Codeforces has finally grow up and it solves its problems itself :D
 » 3 years ago, # |   +6 Mike wrote right thing in the blog : "This round will have a shortened duration of 1.5 hours, consist of 3 (maybe 4) problems that you might have already seen before"I saw this before:First problem : No tasksSecond problem: No coordinatorThird problem : No basketball for me :)It was a good test of our nerves...
 » 3 years ago, # |   +1 there we go, the contest starts 3 hours later :(
 » 3 years ago, # |   0 is there any technical prblm ? I cant see any prblm on testing round ! -_-
 » 3 years ago, # |   -8 I solved E by intersection of half-planes!
•  » » 3 years ago, # ^ |   0 Which E?
•  » » » 3 years ago, # ^ |   0 3 hours later =w=
 » 3 years ago, # |   +14 May be it is the longest delay ever in the history of codforces.
 » 3 years ago, # |   0 this is a real sad story
 » 3 years ago, # |   +8 Am I getting Blind . I can't see any Problem ..... Ummm....
 » 3 years ago, # |   0 we have not enough patience for 3 hours for waiting testing round.
 » 3 years ago, # | ← Rev. 2 →   +12 delay for 3 hours... I choose to die....
 » 3 years ago, # |   +18 Thanks to 3 hours delay, I can now register for the contest. Am I the only one happy about the delay? :D
 » 3 years ago, # |   0 Why postponed?
 » 3 years ago, # | ← Rev. 2 →   +4 Are there enough jokes about testing our patient in comments or I can add another one?
 » 3 years ago, # |   +51
 » 3 years ago, # |   +5 So many hacks today!
 » 3 years ago, # |   0 Educational rounds, I understand, but what was the purpose of this contest?
 » 3 years ago, # |   +2 Awesome competition ! I hacked 12 people on the first task and after that my solution was hacked :)
•  » » 3 years ago, # ^ |   +14 You hacked me and I took revenge :p No offense! :D It was fun :v
•  » » » 3 years ago, # ^ |   +6 Yesm yes :) I made silly mistake :D
•  » » 3 years ago, # ^ |   0 Cool Story, Bro..!
 » 3 years ago, # |   0 My hacking tests for A were 2 1 1 and 3 1 2.
•  » » 3 years ago, # ^ |   +6 I had one test: 2 -4 -3
•  » » 3 years ago, # ^ | ← Rev. 2 →   0 My hacking test for A was 11971 11138 12379
•  » » 3 years ago, # ^ |   0 so, my hacking test was1 -10000000000000000000 1000000000000000000 :D
•  » » » 3 years ago, # ^ |   0 One of the case, my also... :p
•  » » 3 years ago, # ^ |   0 Mine was 2 -20 -19.
 » 3 years ago, # |   0 tnx alot!!!
 » 3 years ago, # |   +3 Small issue I had: After submitting a hack, the verdict on the hacks page was showing "Waiting" for a long time, it only changed to actual verdict after I refreshed the page.
 » 3 years ago, # |   0 good problems ! wish the recent contest problems were as good as this one
 » 3 years ago, # |   +3 It was a hacking contest.... :p
 » 3 years ago, # | ← Rev. 2 →   +3 As in Educational round hacking time is 24 hour's. It will be better if we are allowed to hack outside of our room and the problem we haven't solve. This is because suppose I have found a tricky case in a problem and I could not overcome it during contest. There may have many solution that passed pretest which will fail in this case.
 » 3 years ago, # |   +3 How can we hack solutions after contest or the 24h period isn't for this contest?
•  » » 3 years ago, # ^ |   0 It's for the Educational Round, not this Testing Round.
•  » » » 3 years ago, # ^ |   0 Ah, thank you very much! :)
•  » » 3 years ago, # ^ |   0 24 hour's hacking will be available in Educational rounds.
 » 3 years ago, # |   0 Thanks for the wonderful problems :) Looking forward to the Educational Codeforces Round 1!!
 » 3 years ago, # |   +3 can someone please wrap the solution for C into a few words? thanks in advance
•  » » 3 years ago, # ^ |   +13 The problem can be solved using dp.f[i][k]=number of increasing subsequences of length k that ends at index i.f[i][k]=sum f[j][k-1], j<=i, d[j]
 » 3 years ago, # |   +5 I solved A and B in the contest, but it says "Solved: 1 out of 3" on my contest history. Can someone fix it? Thanks in advance :)
•  » » 3 years ago, # ^ |   0 You probably got hacked at last minute :|I had that happen to me and that killed my exam really.
 » 3 years ago, # | ← Rev. 2 →   +9 Maybe a bug: number of solved problems in this round is not shownUPD: fixed
 » 3 years ago, # |   +2 really awesome :D I hacked 8 , then I discovered that I made a silly mistake in my code I wished I could hack my self :v
 » 3 years ago, # |   0 Will there be any editorial for Testing Round #12? (for problem-C) Anybody who can share the idea of problem C?
•  » » 3 years ago, # ^ |   +6 i solved it with dpdp[i][j] = number of increasing subsequences that end at number i and has the length of jnow : dp[i][j] = dp[1][j-1] + dp[2][j-1] + dp[3][j-1] + ... + dp[i-1][j-1]u can get the following sum with a segment / fenwik tree
 » 3 years ago, # |   +3 Please tell me what is wrong with this solution for C here . I used a BIT to calculate sequences of the length j from sequences of length j-1 which ends in a number less than a[i].
•  » » 3 years ago, # ^ |   +6 idx<=1000006 Shouldn't it be idx <= 100006?
•  » » » 3 years ago, # ^ | ← Rev. 2 →   0 Thank you. I would like to cry now ;;;;;;;___________________;;;;;;;It would've been fine in a 1-dimentional BIT. Screwed up because its 2D.
•  » » » » 3 years ago, # ^ |   +3 100006 → ha ha ha. Wait till you see 1000000007.
•  » » » » » 3 years ago, # ^ |   0 Now I'm strictly moving to 1ex representation :(
 » 3 years ago, # | ← Rev. 2 →   +3 As these are Educational Rounds , do the tutorials contain an explanation of the algorithms [:. An explanation of the algorithm itself.:] used in the questions, or just tell what algorithm was used [:.Explain Only the problem.:] like the rest of the contests ?
•  » » 3 years ago, # ^ |   0 we hope for the better one!!!!!!
•  » » 3 years ago, # ^ |   +5 Should be the latter, right? or else the editorial will be huge. Only difference, the explanation of how the algo/data structure is used will be more detailed. eg: if it has a segment tree, then explaining how the generic segment tree update and queries are made will make the editorial triple in size. But explaining the structure of the nodes should probably be there.
•  » » » 3 years ago, # ^ | ← Rev. 2 →   0 To be honest, I expect a pinch of both, Not too Short, Not too Long. Giving little about the background of the algorithm used [:. Enough Info to search and learn from Other Online resources.:] and more on the whys and hows [:.Not only the usual which algo is best but give insight to why it is used specifically (Over others if any) and how it is modified to fit the problem.:].
 » 3 years ago, # |   0 I don't get one thing though... If they want the rounds to be for educational purposes, shouldn't they be based on particular algorithms/data structures/theory ?
•  » » 3 years ago, # ^ |   0 Part of solving a problem is figuring out which algo to use. By making it unrated, they are discouraging hacks, and you can focus on the problems instead.
 » 3 years ago, # |   0 but also exercises can be used -- what does this mean?
•  » » 3 years ago, # ^ |   +18 I mean that for training purpose we often will use not real problems but just exercises: short and formal task on some specific topic.
•  » » » 3 years ago, # ^ |   +3 ok thnx for reply :)
 » 3 years ago, # |   0 Suggestion: it could be useful to dedicate every Educational Round to some specific topics and declare it's topic and probably list of literature, don't you think so?
 » 3 years ago, # |   0 can i see the data case which my solution failed on after the contest round has ended ,just like cf routine round(div2 and div1) ?
•  » » 3 years ago, # ^ |   0 Yes
 » 3 years ago, # |   0 @MikeMirzayanov and all, Wouldn't it be better to give out resources or material for some topics to read, on which the next Educational Round questions would be created. I am kinda beginner and always stuck on last 3-4 problems and in tutorial I find some of them are on the topics I never have read.
•  » » 3 years ago, # ^ |   +5 But I think knowing the topics on which the problems are based might make it easier to solve! At least I feel so if I know the tag of a problem I am more confident on my solution and thereby Educational round will be like Problem Set to me! You can always try up solving! :) I think that is as knowledgeable as it would have been when you knew the topics!
•  » » » 3 years ago, # ^ |   0 Think with a beginner's point of view, who hasn't even heard of Suffix Tree. Telling that the problem uses DP won't make it easier to think about how to apply DP. And anyway, more resources can be given out so that some of those topics won't be needed and we need to select out which technique can be used. And yes, the motto of Educational series is to make students familiar with different concepts so there must be some resources given out to learn about them. To compete, there is still other Div rounds.
 » 2 years ago, # |   0 Hi, I want to join to this series of rounds and I have some questions: 1. Why it named "Educational"? 2. Is there any plan for these rounds? (e.g any discipline for subject of problems which include in a round) 3. Is there any study program to learn the subjects for this series? 4. What is the prerequisite to take part in rounds? 5. Does it need to solve all the problems in previous rounds (up to now) to join this series or not?
•  » » 2 years ago, # ^ |   0 1.The rounds will educate you with variety of problems and the rounds are not rated. 2.I don't think so. 3.Not really.similar things that you study for other competitive coding. 4.Account on Codeforces which you already have. 5.Nope.
 » 2 years ago, # | ← Rev. 2 →   0 ...
 » 21 month(s) ago, # |   +78 why there are no educational rounds in recent days ?
•  » » 21 month(s) ago, # ^ | ← Rev. 2 →   +4 Mb, because Edvard doesn't work for CODEFORCES anymore?
•  » » » 19 months ago, # ^ |   0 now there is. happy?
 » 19 months ago, # |   0 Let's make educational rounds rated like atcoder. In atcoder beginner contests are rated for beginners. More beginners will participate to rounds.
 » 15 months ago, # |   +8 can anyone tell me where i can find the editorial of codeforces educational round 1 .
 » 10 months ago, # |   0 Is it 13th of October or November?