You can view PDF version of the tutorial by the link.
# | User | Rating |
---|---|---|
1 | ecnerwala | 3648 |
2 | Benq | 3580 |
3 | orzdevinwang | 3570 |
4 | cnnfls_csy | 3569 |
5 | Geothermal | 3568 |
6 | tourist | 3565 |
7 | maroonrk | 3530 |
8 | Radewoosh | 3520 |
9 | Um_nik | 3481 |
10 | jiangly | 3467 |
# | User | Contrib. |
---|---|---|
1 | maomao90 | 174 |
2 | adamant | 164 |
2 | awoo | 164 |
4 | TheScrasse | 160 |
5 | nor | 159 |
6 | maroonrk | 156 |
7 | -is-this-fft- | 150 |
8 | SecondThread | 147 |
9 | orz | 146 |
10 | pajenegod | 145 |
You can view PDF version of the tutorial by the link.
2020-2021 ICPC, NERC, Южный четвертьфинал (онлайн-трансляция, правила ICPC, предпочтительно команды)
Hello!
ICPC Southern and Volga Russian Regional Contest (Northern Eurasia) 2020 has ended on November 15. This year the competition took place online. 108 teams competed, many of them received an invitation based on the results in Qualification Contest.
On Dec/25/2020 14:35 (Moscow time) will start online-mirror 2020-2021 ICPC, NERC, Southern and Volga Russian Regional Contest (Online Mirror, ICPC Rules).
Hope you enjoy the problems. In this contest I play a role of Cheif Judge and the jury teams consists of ex-participants of ICPC from Saratov and jury members from other cities: adedalic, ashmelev, BledDest, DmitryKlenov, DStepanenko, elena, KAN, kuviman, MikeMirzayanov, pashka, PavelKunyavskiy, Дмитрий Мещеряков, Герман Наркайтис. Many thanks to all of them!
I send special rays of gratitude to testers: Merkurev, Um_nik, romanasa, josdas, budalnik, Perforator, Oleg_Smirnov, IlyaLos, Supermagzzz, Stepavly, Igor_Kudryashov, HolkinPV, Edvard, le.mur!
I invite ICPC teams and individual participants of Codeforces competitions to take part!
Of course, the competition will be unrated. I ask the participants of the official competition to refrain from participating in the mirror and discussing problems until its end.
Since this year the audience of participants was wider (due to the online format), we also selected problems a little more accessible than in previous years. If you are from the top team that claims a medal in the ICPC Finals, then it may be more fun for you to take part in this contest personally.
Good luck!
In 2020, with the support of XTX Markets, 6 rounds of the Codeforces Global Rounds were held. Each round was common for both divisions. All such rounds were rated for all participants. At each such round, 50 brand T-shirts were handed out, and we gave T-shirts to all problem writers!
I say a big thank you to XTX Markets (and personally to Yuri Bedny and Alexander Gerko) for supporting Global Rounds. Without your help, we could not host them! I sincerely admire companies like these who come to support and develop the community that some of their employees come from. It will be great if other companies follow the example and also offer their help. We need it!
The prizes for the 6-round series in 2020:
Final results (and congratulations!):
Hello Codeforces!
There is something new for you. It seems that now it will be easier to reuse problems from the archive for educational and other purposes.
As you know, problems from past Codeforces rounds can be added to mashups simply by their codes of the form like 1234D
(contest ID + problem letter). I myself regularly used this when I taught at Saratov University — it was very convenient to prepare trainings: problems have expected complexity and topics, there are Russian and English statements, you can see the analysis and many solutions. Because of hacks and uphacks, problems in the archive usually have strong tests. Almost all of them are well-prepared. In addition, with the help of user lists, you can easily pick up problems for a group of students that they did not solve.
But there was also an issue: the problems in such trainings were easily googled. And if the majority of adult participants could cope with the temptation to spy on the solution or tests, then beginners sometimes acted dishonestly. I received several requests to come up with something with this flaw. One of the most recent such requests was from Daniel Darooha Sleator (https://en.wikipedia.org/wiki/Daniel_Sleator). Thanks, Danny!
So the work seems to be complete. Meet a new feature on Codeforces: now you can rewrite statements for problems in mashups, completely replacing it with your own. More details about the capabilities of the new functionality:
Considering that there are already more than 6500 problems in the archive, an excellent perspective opens up for organizing trainings and educational sessions.
I hope this innovation will be useful. Write in the comments what can be improved and/or corrected.
M.
During the round Grakn Forces 2020 many of you can notice that now we highlight diff in statements if they changed. Do you like this new feature?
Also, I'm thinking on the way to automatically notify participants if statements changed. I still do not fully understand how this should ideally be implemented. Sometimes it is true that just a forgotten comma was added. On the other hand, it is almost always better to notify of changes. What do you think?
In 2020 (as in 2019), with the support of XTX Markets, 6 rounds of the new Codeforces Global Rounds will be held. These will be common rounds for both divisions of 7–9 problems each. The duration of the rounds will be 2-3 hours, depending on the number and complexity of the problems. All such rounds will be rated for all participants. At each such round, 50 brand T-shirts will be handed out, and we will be happy to give T-shirts to all problem authors and problem testers.
The prizes for the 6-round series in 2020:
Current standings after four rounds (sorted by total points in four rounds):
Place | Contestant | = | GR 7 | GR 8 | GR 9 | GR 10 |
---|---|---|---|---|---|---|
1 | tourist | 3203 | 1000 | 706 | 1000 | 497 |
2 | ecnerwala | 1841 | 235 | 1000 | 31 | 575 |
3 | Um_nik | 1606 | 706 | 403 | 497 | — |
4 | boboniu | 1575 | 575 | — | — | 1000 |
5 | maroonrk | 1278 | 149 | 371 | 52 | 706 |
6 | Petr | 990 | — | 497 | 50 | 443 |
7 | yosupo | 978 | 211 | — | 575 | 192 |
8 | sunset | 803 | 291 | — | 166 | 346 |
9 | Benq | 769 | 307 | 176 | 21 | 265 |
10 | ksun48 | 736 | 122 | — | 211 | 403 |
11 | LayCurse | 716 | — | 171 | 291 | 254 |
12 | scott_wu | 706 | — | — | 706 | — |
13 | Radewoosh | 703 | 244 | 443 | 16 | — |
14 | Egor | 690 | 107 | 265 | 74 | 244 |
15 | hos.lyric | 661 | 128 | — | 226 | 307 |
16 | TLEwpdus | 651 | — | 235 | 198 | 218 |
17 | jiangly | 646 | 497 | — | 149 | — |
18 | Swistakk | 602 | 277 | 90 | 235 | — |
19 | hank55663 | 588 | 74 | 291 | 78 | 145 |
20 | neal | 584 | 131 | 277 | 176 | — |
21 | Marcin_smu | 575 | — | 575 | — | — |
22 | zeronumber | 564 | — | 68 | 325 | 171 |
23 | 244mhq | 523 | 325 | 198 | — | — |
24 | KAN | 511 | — | 307 | — | 204 |
25 | Itst_boyfriend | 493 | 94 | 92 | 307 | — |
26 | conqueror_of_tourist | 470 | — | — | 244 | 226 |
27 | cuizhuyefei | 443 | 443 | — | — | — |
27 | Rewinding | 443 | — | — | 443 | — |
29 | tmwilliamlin168 | 441 | — | — | 70 | 371 |
30 | Golovanov399 | 438 | 161 | — | 277 | — |
31 | lqs2015 | 424 | 21 | — | 403 | — |
32 | snuke | 420 | 32 | 325 | — | 63 |
33 | whzzt | 417 | — | — | 92 | 325 |
34 | Motarack | 404 | — | 58 | 346 | — |
35 | TLE | 403 | 403 | — | — | — |
36 | heno239 | 400 | 29 | — | 371 | — |
37 | mango_lassi | 393 | 138 | 153 | — | 102 |
38 | eatmore | 375 | — | 346 | — | 29 |
39 | WZYYN | 371 | 371 | — | — | — |
40 | Errichto | 367 | — | 186 | — | 181 |
41 | dreamoon_love_AA | 354 | — | 119 | — | 235 |
41 | PavelKunyavskiy | 354 | 346 | — | 8 | — |
43 | ko_osaga | 348 | 226 | — | — | 122 |
44 | Noam527 | 346 | 142 | 204 | — | — |
45 | uwi | 342 | — | 211 | — | 131 |
46 | natsugiri | 341 | — | 192 | 149 | — |
47 | aid | 339 | 254 | 85 | — | — |
47 | duality | 339 | 153 | — | — | 186 |
49 | qwerty787788 | 330 | — | — | 39 | 291 |
49 | Maksim1744 | 330 | 181 | — | — | 149 |
51 | kort0n | 304 | 34 | — | 157 | 113 |
52 | Yongaron | 292 | — | 161 | 131 | — |
53 | molamola. | 277 | — | — | — | 277 |
54 | frodakcin | 276 | — | 254 | — | 22 |
55 | SirShokoladina | 266 | — | 105 | 161 | — |
56 | RomaWhite | 265 | 265 | — | — | — |
56 | mrscherry | 265 | — | — | 265 | — |
58 | Merkurev | 261 | — | 142 | — | 119 |
58 | ainta | 261 | 63 | — | — | 198 |
60 | mtsd | 258 | — | 145 | 113 | — |
61 | EnEm | 254 | — | — | 254 | — |
62 | xiaowuc1 | 244 | — | 244 | — | — |
63 | nonamefour0210 | 243 | — | — | 32 | 211 |
64 | orz | 226 | — | 226 | — | — |
65 | gop2024 | 220 | 16 | — | 204 | — |
65 | nuip | 220 | — | 128 | — | 92 |
67 | ohweonfire | 218 | — | — | 218 | — |
67 | DCXDCX | 218 | 218 | — | — | — |
67 | 79brue | 218 | — | 218 | — | — |
70 | tatyam | 214 | — | 138 | — | 76 |
71 | Ilya_MSU | 209 | — | 74 | 125 | 10 |
72 | amnesiac_dusk | 204 | 204 | — | — | — |
73 | stevenkplus | 202 | 21 | — | 181 | — |
74 | djq_fpc | 198 | 198 | — | — | — |
75 | zeliboba | 193 | 27 | 166 | — | — |
76 | HashimotoNanami | 192 | — | — | 192 | — |
76 | _h_ | 192 | — | 161 | — | 31 |
76 | .I. | 192 | 192 | — | — | — |
79 | Egor.Lifar | 186 | 186 | — | — | — |
79 | Sulfox | 186 | — | — | 186 | — |
81 | dario2994 | 181 | 135 | — | — | 46 |
81 | jhnan917 | 181 | — | 181 | — | — |
83 | kmjp | 177 | 105 | — | — | 72 |
84 | FizzyDavid | 176 | 176 | — | — | — |
84 | atomicenergy | 176 | — | — | — | 176 |
86 | Amoo_Safar | 175 | 4 | — | 171 | — |
87 | receed | 174 | — | — | 13 | 161 |
88 | nick452 | 171 | — | 43 | — | 128 |
88 | tribute_to_Ukraine_2022 | 171 | 171 | — | — | — |
90 | okikust | 166 | — | — | — | 166 |
90 | craborac | 166 | 166 | — | — | — |
92 | imeimi | 157 | — | — | — | 157 |
92 | cookiedoth | 157 | 157 | — | — | — |
94 | risujiroh | 153 | — | — | — | 153 |
94 | chokudai | 153 | — | 153 | — | — |
94 | zylber | 153 | — | — | 153 | — |
97 | never_giveup | 145 | 145 | — | — | — |
98 | Muffinhead | 142 | — | — | — | 142 |
98 | GreymaneSilverfang | 142 | — | — | 142 | — |
98 | YeongTree | 142 | — | — | 80 | 62 |
101 | Toxel | 138 | — | — | — | 138 |
101 | Shayan | 138 | — | — | 138 | — |
103 | RNS_CUS | 135 | — | — | 135 | — |
103 | hepth | 135 | — | 135 | — | — |
103 | budalnik | 135 | — | — | — | 135 |
106 | dyxg | 131 | — | — | 131 | — |
106 | ATS | 131 | — | 131 | — | — |
108 | JettyOller | 129 | 39 | — | — | 90 |
109 | LHiC | 128 | 92 | — | 36 | — |
110 | lzr_010506 | 125 | — | — | 99 | 26 |
110 | primenumber | 125 | — | — | — | 125 |
110 | Martin53 | 125 | — | 125 | — | — |
110 | sigma425 | 125 | 125 | — | — | — |
114 | Chelly | 124 | — | — | 56 | 68 |
115 | littlelittlehorse | 122 | — | — | 122 | — |
115 | dlalswp25 | 122 | — | — | 122 | — |
115 | Potassium | 122 | — | 122 | — | — |
118 | Tima | 119 | 119 | — | — | — |
119 | yhx-12243 | 117 | 72 | — | 45 | — |
120 | blackbori | 116 | — | — | — | 116 |
120 | yokozuna57 | 116 | — | 116 | — | — |
120 | PinkieRabbit | 116 | — | — | 116 | — |
120 | betrue12 | 116 | 116 | — | — | — |
120 | SSRS_ | 116 | — | 50 | — | 66 |
125 | MofK | 115 | 102 | — | — | 13 |
126 | Pigbrain | 113 | 113 | — | — | — |
126 | zhangguangxuan99 | 113 | — | 113 | — | — |
128 | oopsimbad | 110 | — | 110 | — | — |
128 | Jacob | 110 | — | — | — | 110 |
128 | tempura0224 | 110 | 110 | — | — | — |
128 | Eliden | 110 | — | — | 110 | — |
132 | yashChandnani | 107 | — | 107 | — | — |
132 | LynCean | 107 | — | — | — | 107 |
132 | Temotoloraia | 107 | — | — | 107 | — |
135 | Reyna | 106 | — | 72 | 34 | — |
136 | kriii | 105 | — | — | 105 | — |
136 | pashka | 105 | — | — | — | 105 |
138 | BlackPuppy | 102 | — | — | 102 | — |
138 | Thienu | 102 | — | 102 | — | — |
140 | Roundgod | 101 | — | 41 | — | 60 |
141 | antontrygubO_o | 100 | 1 | 99 | — | — |
142 | Sugar_fan | 99 | — | — | — | 99 |
142 | mayaohua | 99 | 99 | — | — | — |
144 | skylinebaby | 97 | — | — | 97 | — |
144 | neko_nyaaaaaaaaaaaaaaaaa | 97 | — | — | — | 97 |
144 | shino16 | 97 | — | 97 | — | — |
144 | zscoder | 97 | 97 | — | — | — |
148 | Eternal_Dream | 94 | — | — | 94 | — |
148 | ollpu | 94 | — | 94 | — | — |
148 | riadwaw | 94 | — | — | — | 94 |
151 | jdurie | 93 | — | 37 | — | 56 |
152 | penguin1017 | 92 | — | 14 | 78 | — |
153 | weishenme | 90 | 90 | — | — | — |
153 | est_stella | 90 | — | — | 90 | — |
155 | yuma_ | 87 | — | — | 87 | — |
155 | Konijntje | 87 | — | — | — | 87 |
155 | mnbvmar | 87 | 87 | — | — | — |
155 | icecuber | 87 | — | 87 | — | — |
159 | KayacanV | 85 | — | — | 85 | — |
159 | Rubikun | 85 | — | — | — | 85 |
159 | kobae964 | 85 | 85 | — | — | — |
162 | stupid_american | 83 | — | — | 83 | — |
162 | Farhod | 83 | 83 | — | — | — |
162 | BigBag | 83 | — | — | — | 83 |
162 | shenxy13 | 83 | — | 83 | — | — |
166 | turmax | 80 | — | 80 | — | — |
166 | sevlll777 | 80 | — | — | — | 80 |
166 | GaloisTears | 80 | 80 | — | — | — |
169 | Gassa | 78 | — | 78 | — | — |
169 | crazyilian | 78 | — | — | — | 78 |
169 | znirzej | 78 | 78 | — | — | — |
172 | little_misfortune | 76 | 76 | — | — | — |
172 | Antoine | 76 | — | 76 | — | — |
174 | Alex_2oo8 | 74 | — | — | — | 74 |
175 | disangan233 | 72 | — | — | 72 | — |
175 | falanga | 72 | — | — | — | 72 |
177 | hugopm | 70 | — | 70 | — | — |
177 | MicGor | 70 | 70 | — | — | — |
179 | Egg_Tart_Forest | 68 | 68 | — | — | — |
179 | saba2000 | 68 | — | — | 10 | 58 |
179 | upobir | 68 | — | — | 68 | — |
182 | xuanyi | 66 | — | — | 66 | — |
182 | paula | 66 | 66 | — | — | — |
182 | Shef | 66 | — | 66 | — | — |
185 | JiriKalvoda | 63 | — | 63 | — | — |
185 | gazelle | 63 | — | — | 63 | — |
185 | TadijaSebez | 63 | 63 | — | — | — |
185 | nocriz | 63 | 63 | — | — | — |
189 | nhho | 62 | — | 62 | — | — |
189 | Isonan | 62 | — | — | 62 | — |
191 | JeffreyLC | 61 | — | 45 | — | 16 |
192 | Geothermal | 60 | — | — | 60 | — |
192 | Savior-of-Cross | 60 | — | 60 | — | — |
194 | noimi | 58 | — | — | 58 | — |
194 | wucstdio | 58 | 48 | 10 | — | — |
194 | Kostroma | 58 | 58 | — | — | — |
197 | CKP_ | 56 | — | 56 | — | — |
197 | hitonanode | 56 | 56 | — | — | — |
199 | chenjb | 55 | 36 | — | — | 19 |
200 | errorgorn | 54 | — | 54 | — | — |
200 | Fuyuki | 54 | — | — | 54 | — |
200 | Kiri8128 | 54 | — | — | — | 54 |
200 | cescmentation_folch | 54 | 54 | — | — | — |
204 | Retro3014 | 52 | 52 | — | — | — |
204 | Ali.Kh | 52 | — | — | — | 52 |
204 | QwertyPi | 52 | — | 52 | — | — |
207 | aaaaajack | 50 | 50 | — | — | — |
207 | ttttan | 50 | — | — | — | 50 |
209 | RNS_MHB | 48 | — | — | 48 | — |
209 | misty1999 | 48 | — | 48 | — | — |
209 | awoo | 48 | — | — | — | 48 |
212 | NotaMotuaQAQ | 46 | 46 | — | — | — |
212 | majk | 46 | — | — | 46 | — |
212 | tonyjjw | 46 | — | 46 | — | — |
215 | MAOoo_Love_Molly | 45 | — | — | — | 45 |
215 | vepifanov | 45 | 45 | — | — | — |
217 | jklepec | 43 | 43 | — | — | — |
217 | Morokei | 43 | — | — | 43 | — |
217 | Rewritetxdy | 43 | — | — | — | 43 |
220 | skip2004 | 41 | 41 | — | — | — |
220 | Volkov_Ivan | 41 | — | — | — | 41 |
220 | Zayin | 41 | — | — | 41 | — |
223 | celesta | 39 | 8 | 31 | — | — |
223 | balbit | 39 | — | — | 39 | — |
223 | pwypeanut | 39 | — | 39 | — | — |
223 | wangziji | 39 | — | — | — | 39 |
227 | Nachia | 38 | — | — | 22 | 16 |
228 | VladaMG98 | 37 | — | — | — | 37 |
228 | pupiI | 37 | 37 | — | — | — |
230 | Kalptaru | 36 | — | — | — | 36 |
230 | loup | 36 | — | 36 | — | — |
232 | oscar114514 | 34 | — | — | — | 34 |
232 | EricHuang2003 | 34 | — | 34 | — | — |
234 | jtnydv25 | 32 | — | — | — | 32 |
234 | rstoick | 32 | — | 32 | — | — |
236 | cdkrot | 31 | 31 | — | — | — |
237 | J_J_ | 29 | — | — | 29 | — |
237 | nigus | 29 | — | 29 | — | — |
237 | ForeverFire | 29 | — | — | 29 | — |
240 | Will_Dearborn | 27 | — | — | — | 27 |
240 | AndreySergunin | 27 | — | 27 | — | — |
242 | Tweetuzki | 26 | — | — | 26 | — |
242 | AlesyaIvanova | 26 | — | — | — | 26 |
242 | nagpaljatin1411 | 26 | — | 26 | — | — |
242 | darnley | 26 | 26 | — | — | — |
246 | Aeon | 24 | — | 24 | — | — |
246 | gepardo | 24 | — | — | 24 | — |
246 | oversolver | 24 | 24 | — | — | — |
249 | xtqqwq | 22 | 22 | — | — | — |
249 | KAP | 22 | — | 22 | — | — |
251 | yao11617 | 21 | — | 21 | — | — |
251 | Pa.Nic | 21 | — | — | — | 21 |
253 | Apsara | 19 | — | 19 | — | — |
253 | kotatsugame | 19 | — | — | 19 | — |
253 | kotamanegi | 19 | — | — | — | 19 |
256 | Ari | 17 | — | 17 | — | — |
256 | dorijanlendvaj | 17 | 17 | — | — | — |
256 | low_ | 17 | — | — | 17 | — |
259 | nikolapesic2802 | 16 | — | 16 | — | — |
259 | Akulyat | 16 | — | — | 11 | 5 |
261 | KrK | 14 | — | — | 14 | — |
261 | jiangly_fan | 14 | 14 | — | — | — |
263 | summitwei | 13 | — | 13 | — | — |
263 | AutumnKite | 13 | 13 | — | — | — |
263 | AliShahali1382 | 13 | 13 | — | — | — |
266 | Wild_Hamster | 11 | — | 11 | — | — |
266 | qhqh | 11 | — | — | — | 11 |
268 | boook | 10 | — | — | — | 10 |
268 | tnowak | 10 | 10 | — | — | — |
270 | ehnryx | 8 | — | 8 | — | — |
271 | m_99 | 7 | — | — | — | 7 |
271 | krijgertje | 7 | 7 | — | — | — |
271 | Tlatoani | 7 | — | 7 | — | — |
271 | Cyprien | 7 | — | — | 7 | — |
275 | vasilescu_mihai | 5 | 5 | — | — | — |
275 | osmanorhan | 5 | — | — | 5 | — |
275 | primaryStu | 5 | — | — | 5 | — |
275 | kpw29 | 5 | — | — | — | 5 |
275 | baqargam | 5 | — | 5 | — | — |
280 | amethyst0 | 4 | — | 4 | — | — |
281 | user202729_ | 2 | — | 2 | — | — |
281 | daifucong | 2 | 2 | — | — | — |
281 | -eidolon- | 2 | — | — | — | 2 |
281 | ekaerovets | 2 | — | — | 2 | — |
285 | mphillotry | 1 | — | — | — | 1 |
285 | SPatrik | 1 | — | 1 | — | — |
285 | Mojumbo | 1 | — | — | 1 | — |
Hello!
This is just a small announcement of the latest updates in EDU. New features:
Now you can view other's solutions if you have solved the problem yourself. I think this can be very useful. When I I was a contest participant, I always looked as others who are more experienced than me wrote this or that code. Often found something interesting and useful.
Now you can view tests for problems in the format, as it is done in the archive in the main section of the website.
Now you can hack other people's solutions if you have solved the problem yourself. And fun and will improve tests of these problems.
More about EDU section you can read in this post.
And what are your wishes for functionality? I remember about filtering the results of practice by friends.
UPD: And for all practice contests I have set a policy of "use time limits scaling policy". This is a recent innovation — you can use it for educational contests, the system will automatically increase the time limit for some languages. Recommended for use only in educational contests.
Hello.
Last days I did many improvements in EDU. I afraid it can affect the contest interface. So I invite you to take part in [contest:1390], just to test the system. Please, try to hacks: there were some changes in them. Please, don't expect new or interesting problems. It is just a test. Unrated.
The problems contain extremely weak pretests. Time limits are too tight. I made my best to increase number of hacks :-)
Thanks, Mike.
UPD: Thanks! It seems no bugs have been found.
Hello.
Unfortunately, the Educational Codeforces Round 91 round will be unrated and, actually, it was completely ruined. I don’t understand what happened yet. At some point in time, all systems began to work unstably and actually stopped working. So far I have no understanding what happened. You may have to change the schedule for future rounds. Sorry. We have such a black stripe. Very upset and demotivated.
Mike.
In 2020 (as in 2019), with the support of XTX Markets, 6 rounds of the new Codeforces Global Rounds will be held. These will be common rounds for both divisions of 7–9 problems each. The duration of the rounds will be 2-3 hours, depending on the number and complexity of the problems. All such rounds will be rated for all participants. At each such round, 50 brand T-shirts will be handed out, and we will be happy to give T-shirts to all problem authors and problem testers.
The prizes for the 6-round series in 2020:
Current standings after three rounds (sorted by total points in three rounds):
Place | Contestant | = | GR 7 | GR 8 | GR 9 |
---|---|---|---|---|---|
1 | tourist | 2706 | 1000 | 706 | 1000 |
2 | Um_nik | 1606 | 706 | 403 | 497 |
3 | ecnerwala | 1266 | 235 | 1000 | 31 |
4 | yosupo | 786 | 211 | — | 575 |
5 | scott_wu | 706 | — | — | 706 |
6 | Radewoosh | 703 | 244 | 443 | 16 |
7 | jiangly | 646 | 497 | — | 149 |
8 | Swistakk | 602 | 277 | 90 | 235 |
9 | neal | 584 | 131 | 277 | 176 |
10 | Marcin_smu | 575 | — | 575 | — |
10 | boboniu | 575 | 575 | — | — |
12 | maroonrk | 572 | 149 | 371 | 52 |
13 | Petr | 547 | — | 497 | 50 |
14 | 244mhq | 523 | 325 | 198 | — |
15 | Benq | 504 | 307 | 176 | 21 |
16 | Itst_boyfriend | 493 | 94 | 92 | 307 |
17 | LayCurse | 462 | — | 171 | 291 |
18 | sunset | 457 | 291 | — | 166 |
19 | Egor | 446 | 107 | 265 | 74 |
20 | hank55663 | 443 | 74 | 291 | 78 |
20 | cuizhuyefei | 443 | 443 | — | — |
20 | Rewinding | 443 | — | — | 443 |
23 | Golovanov399 | 438 | 161 | — | 277 |
24 | TLEwpdus | 433 | — | 235 | 198 |
25 | lqs2015 | 424 | 21 | — | 403 |
26 | Motarack | 404 | — | 58 | 346 |
27 | TLE | 403 | 403 | — | — |
28 | heno239 | 400 | 29 | — | 371 |
29 | zeronumber | 393 | — | 68 | 325 |
30 | WZYYN | 371 | 371 | — | — |
31 | snuke | 357 | 32 | 325 | — |
32 | hos.lyric | 354 | 128 | — | 226 |
32 | PavelKunyavskiy | 354 | 346 | — | 8 |
34 | eatmore | 346 | — | 346 | — |
34 | Noam527 | 346 | 142 | 204 | — |
36 | natsugiri | 341 | — | 192 | 149 |
37 | aid | 339 | 254 | 85 | — |
38 | ksun48 | 333 | 122 | — | 211 |
39 | KAN | 307 | — | 307 | — |
40 | Yongaron | 292 | — | 161 | 131 |
41 | mango_lassi | 291 | 138 | 153 | — |
42 | SirShokoladina | 266 | — | 105 | 161 |
43 | RomaWhite | 265 | 265 | — | — |
43 | mrscherry | 265 | — | — | 265 |
45 | mtsd | 258 | — | 145 | 113 |
46 | EnEm | 254 | — | — | 254 |
46 | frodakcin | 254 | — | 254 | — |
48 | xiaowuc1 | 244 | — | 244 | — |
48 | conqueror_of_tourist | 244 | — | — | 244 |
50 | ko_osaga | 226 | 226 | — | — |
50 | orz | 226 | — | 226 | — |
52 | gop2024 | 220 | 16 | — | 204 |
53 | ohweonfire | 218 | — | — | 218 |
53 | DCXDCX | 218 | 218 | — | — |
53 | 79brue | 218 | — | 218 | — |
56 | uwi | 211 | — | 211 | — |
57 | amnesiac_dusk | 204 | 204 | — | — |
58 | stevenkplus | 202 | 21 | — | 181 |
59 | Ilya_MSU | 199 | — | 74 | 125 |
60 | djq_fpc | 198 | 198 | — | — |
61 | zeliboba | 193 | 27 | 166 | — |
62 | HashimotoNanami | 192 | — | — | 192 |
62 | .I. | 192 | 192 | — | — |
64 | kort0n | 191 | 34 | — | 157 |
65 | Egor.Lifar | 186 | 186 | — | — |
65 | Sulfox | 186 | — | — | 186 |
65 | Errichto | 186 | — | 186 | — |
68 | Maksim1744 | 181 | 181 | — | — |
68 | jhnan917 | 181 | — | 181 | — |
70 | FizzyDavid | 176 | 176 | — | — |
71 | Amoo_Safar | 175 | 4 | — | 171 |
72 | tribute_to_Ukraine_2022 | 171 | 171 | — | — |
73 | craborac | 166 | 166 | — | — |
74 | _h_ | 161 | — | 161 | — |
75 | cookiedoth | 157 | 157 | — | — |
76 | chokudai | 153 | — | 153 | — |
76 | zylber | 153 | — | — | 153 |
76 | duality | 153 | 153 | — | — |
79 | never_giveup | 145 | 145 | — | — |
80 | Merkurev | 142 | — | 142 | — |
80 | GreymaneSilverfang | 142 | — | — | 142 |
82 | tatyam | 138 | — | 138 | — |
82 | Shayan | 138 | — | — | 138 |
84 | RNS_CUS | 135 | — | — | 135 |
84 | hepth | 135 | — | 135 | — |
84 | dario2994 | 135 | 135 | — | — |
87 | dyxg | 131 | — | — | 131 |
87 | ATS | 131 | — | 131 | — |
89 | nuip | 128 | — | 128 | — |
89 | LHiC | 128 | 92 | — | 36 |
91 | Martin53 | 125 | — | 125 | — |
91 | sigma425 | 125 | 125 | — | — |
93 | littlelittlehorse | 122 | — | — | 122 |
93 | dlalswp25 | 122 | — | — | 122 |
93 | Potassium | 122 | — | 122 | — |
96 | Tima | 119 | 119 | — | — |
96 | dreamoon_love_AA | 119 | — | 119 | — |
98 | yhx-12243 | 117 | 72 | — | 45 |
99 | yokozuna57 | 116 | — | 116 | — |
99 | PinkieRabbit | 116 | — | — | 116 |
99 | betrue12 | 116 | 116 | — | — |
102 | Pigbrain | 113 | 113 | — | — |
102 | zhangguangxuan99 | 113 | — | 113 | — |
104 | oopsimbad | 110 | — | 110 | — |
104 | tempura0224 | 110 | 110 | — | — |
104 | Eliden | 110 | — | — | 110 |
107 | yashChandnani | 107 | — | 107 | — |
107 | Temotoloraia | 107 | — | — | 107 |
109 | Reyna | 106 | — | 72 | 34 |
110 | kmjp | 105 | 105 | — | — |
110 | kriii | 105 | — | — | 105 |
112 | BlackPuppy | 102 | — | — | 102 |
112 | Thienu | 102 | — | 102 | — |
112 | MofK | 102 | 102 | — | — |
115 | antontrygubO_o | 100 | 1 | 99 | — |
116 | lzr_010506 | 99 | — | — | 99 |
116 | mayaohua | 99 | 99 | — | — |
118 | skylinebaby | 97 | — | — | 97 |
118 | shino16 | 97 | — | 97 | — |
118 | zscoder | 97 | 97 | — | — |
121 | Eternal_Dream | 94 | — | — | 94 |
121 | ollpu | 94 | — | 94 | — |
123 | whzzt | 92 | — | — | 92 |
123 | penguin1017 | 92 | — | 14 | 78 |
125 | weishenme | 90 | 90 | — | — |
125 | est_stella | 90 | — | — | 90 |
127 | yuma_ | 87 | — | — | 87 |
127 | mnbvmar | 87 | 87 | — | — |
127 | icecuber | 87 | — | 87 | — |
130 | KayacanV | 85 | — | — | 85 |
130 | kobae964 | 85 | 85 | — | — |
132 | stupid_american | 83 | — | — | 83 |
132 | Farhod | 83 | 83 | — | — |
132 | shenxy13 | 83 | — | 83 | — |
135 | turmax | 80 | — | 80 | — |
135 | GaloisTears | 80 | 80 | — | — |
135 | YeongTree | 80 | — | — | 80 |
138 | Gassa | 78 | — | 78 | — |
138 | znirzej | 78 | 78 | — | — |
140 | little_misfortune | 76 | 76 | — | — |
140 | Antoine | 76 | — | 76 | — |
142 | disangan233 | 72 | — | — | 72 |
143 | tmwilliamlin168 | 70 | — | — | 70 |
143 | hugopm | 70 | — | 70 | — |
143 | MicGor | 70 | 70 | — | — |
146 | Egg_Tart_Forest | 68 | 68 | — | — |
146 | upobir | 68 | — | — | 68 |
148 | xuanyi | 66 | — | — | 66 |
148 | paula | 66 | 66 | — | — |
148 | Shef | 66 | — | 66 | — |
151 | JiriKalvoda | 63 | — | 63 | — |
151 | gazelle | 63 | — | — | 63 |
151 | TadijaSebez | 63 | 63 | — | — |
151 | nocriz | 63 | 63 | — | — |
151 | ainta | 63 | 63 | — | — |
156 | nhho | 62 | — | 62 | — |
156 | Isonan | 62 | — | — | 62 |
158 | Geothermal | 60 | — | — | 60 |
158 | Savior-of-Cross | 60 | — | 60 | — |
160 | noimi | 58 | — | — | 58 |
160 | wucstdio | 58 | 48 | 10 | — |
160 | Kostroma | 58 | 58 | — | — |
163 | Chelly | 56 | — | — | 56 |
163 | CKP_ | 56 | — | 56 | — |
163 | hitonanode | 56 | 56 | — | — |
166 | errorgorn | 54 | — | 54 | — |
166 | Fuyuki | 54 | — | — | 54 |
166 | cescmentation_folch | 54 | 54 | — | — |
169 | Retro3014 | 52 | 52 | — | — |
169 | QwertyPi | 52 | — | 52 | — |
171 | aaaaajack | 50 | 50 | — | — |
171 | SSRS_ | 50 | — | 50 | — |
173 | RNS_MHB | 48 | — | — | 48 |
173 | misty1999 | 48 | — | 48 | — |
175 | NotaMotuaQAQ | 46 | 46 | — | — |
175 | majk | 46 | — | — | 46 |
175 | tonyjjw | 46 | — | 46 | — |
178 | vepifanov | 45 | 45 | — | — |
178 | JeffreyLC | 45 | — | 45 | — |
180 | nick452 | 43 | — | 43 | — |
180 | jklepec | 43 | 43 | — | — |
180 | Morokei | 43 | — | — | 43 |
183 | skip2004 | 41 | 41 | — | — |
183 | Zayin | 41 | — | — | 41 |
183 | Roundgod | 41 | — | 41 | — |
186 | qwerty787788 | 39 | — | — | 39 |
186 | celesta | 39 | 8 | 31 | — |
186 | balbit | 39 | — | — | 39 |
186 | pwypeanut | 39 | — | 39 | — |
186 | JettyOller | 39 | 39 | — | — |
191 | jdurie | 37 | — | 37 | — |
191 | pupiI | 37 | 37 | — | — |
193 | chenjb | 36 | 36 | — | — |
193 | loup | 36 | — | 36 | — |
195 | EricHuang2003 | 34 | — | 34 | — |
196 | nonamefour0210 | 32 | — | — | 32 |
196 | rstoick | 32 | — | 32 | — |
198 | cdkrot | 31 | 31 | — | — |
199 | J_J_ | 29 | — | — | 29 |
199 | nigus | 29 | — | 29 | — |
199 | ForeverFire | 29 | — | — | 29 |
202 | AndreySergunin | 27 | — | 27 | — |
203 | Tweetuzki | 26 | — | — | 26 |
203 | nagpaljatin1411 | 26 | — | 26 | — |
203 | darnley | 26 | 26 | — | — |
206 | Aeon | 24 | — | 24 | — |
206 | gepardo | 24 | — | — | 24 |
206 | oversolver | 24 | 24 | — | — |
209 | Nachia | 22 | — | — | 22 |
209 | xtqqwq | 22 | 22 | — | — |
209 | KAP | 22 | — | 22 | — |
212 | yao11617 | 21 | — | 21 | — |
213 | Apsara | 19 | — | 19 | — |
213 | kotatsugame | 19 | — | — | 19 |
215 | Ari | 17 | — | 17 | — |
215 | dorijanlendvaj | 17 | 17 | — | — |
215 | low_ | 17 | — | — | 17 |
218 | nikolapesic2802 | 16 | — | 16 | — |
219 | KrK | 14 | — | — | 14 |
219 | jiangly_fan | 14 | 14 | — | — |
221 | summitwei | 13 | — | 13 | — |
221 | AutumnKite | 13 | 13 | — | — |
221 | AliShahali1382 | 13 | 13 | — | — |
221 | receed | 13 | — | — | 13 |
225 | Wild_Hamster | 11 | — | 11 | — |
225 | Akulyat | 11 | — | — | 11 |
227 | saba2000 | 10 | — | — | 10 |
227 | tnowak | 10 | 10 | — | — |
229 | ehnryx | 8 | — | 8 | — |
230 | krijgertje | 7 | 7 | — | — |
230 | Tlatoani | 7 | — | 7 | — |
230 | Cyprien | 7 | — | — | 7 |
233 | vasilescu_mihai | 5 | 5 | — | — |
233 | osmanorhan | 5 | — | — | 5 |
233 | primaryStu | 5 | — | — | 5 |
233 | baqargam | 5 | — | 5 | — |
237 | amethyst0 | 4 | — | 4 | — |
238 | user202729_ | 2 | — | 2 | — |
238 | daifucong | 2 | 2 | — | — |
238 | ekaerovets | 2 | — | — | 2 |
241 | SPatrik | 1 | — | 1 | — |
241 | Mojumbo | 1 | — | — | 1 |
Hello Codeforces!
In February, in the Russian-language interface, we announced a new educational subsection of the website. It's time to go international!
I am pleased to invite you to test the new section, which so far has the working title EDU. I hope that someday EDU will become a real educational hub for fans of programming competitions. It will be great to have in one place the collected educational content with text and video materials, with selected thematic problems.
At the moment, its functionality is still under development, and here is the current progress and β-testing preview. Write your comments and suggestions in the comments here.
So far, only a pilot course with the first lesson "Suffix Array" has been presented to your attention. The plans include expanding both the functionality of the section and filling it with new content.
Russian version already contains more lessons. At the moment, it is important for us to get the first feedback from international users. Many thanks to Pavel Mavrin (pashka) for preparing the first English lesson. Please support pashka to motivate him to translate more lessons!
I hope that in the future, using the materials in this section, you will be able to gain knowledge on an extensive set of topics that are used in contests and olympiads. According to the current plan, a group of ITMO lecturers and students will be engaged in a pilot course, a little later we will consider the possibility of opening the possibility of creating classes for a wider audience.
Thanks to ITMO University for the idea and support for the implementation of this initiative!
Hello!
Together with colleagues Schaffhausen Institute of Technology we hold such an event. If you want to study in Switzerland, then perhaps this is your chance!
— Mike
Hello, Codeforces!
We are thrilled to announce a new SIT STAR Contest by the Schaffhausen Institute of Technology in Switzerland. The winners will have a chance to get a fully-funded Master’s scholarship in Computer Science and Software Engineering.
What is the SIT STAR Contest?
The goal of the SIT STAR Contest is to promote interest in the field of Computer Science and Software Engineering, give students an opportunity to demonstrate their knowledge of programming, and be considered for a fully-funded graduate scholarship. You can apply to the contest here!
The SIT STAR Contest consists of:
The SIT STAR Contest will include 8-12 problems of various levels of difficulty in algorithmic programming.
Hello, Codeforces!
I carefully read most of the ideas that are written in the comments and posts. I have no way to answer everything. Otherwise, I would only do what I answered. Excuse me. There are many good ideas, some easier to implement, some more difficult.
The following idea seems vivid to me. Idea is to limit the maximum rating increase for rounds where there is already an upper rating limit at registration. For example, if the upper limit is $$$u$$$, then your rating after participating in the round cannot be higher than $$$u+100$$$ even with a very successful performance. For example, after winning in Div.3 round the rating can't be more than $$$1699$$$.
It is easy to implement, it does not entail a significant redistribution of ratings. It seems I like it. What do you think about it?
Actually, probably a good idea is to make a bottom cap for rating changes: in any case of any (even the worst) performance, the rating shall not fall by more than $$$100$$$. Еverything happens during the rounds — there may be technical difficulties, force majeure, or just catastrophic bad luck. What are your thoughts about it?
— Mike
Hello everyone.
In the coming days I will finish the implementation of small changes in the rating calculation for new accounts. Here are the main innovations.
Thus, on average, for new accounts at an early stage, the rating will increase, getting closer to the real value. These innovations will help solve several issues:
Apparently, a similar idea is used on AtCoder, but I don't know the details.
What do you think about such improvement? Sounds good?
I almost copied my previous blog post to separate two discussions: about Div. 4 in general and about Round 640. Please, visit this blog post to discuss Div. 4 rounds.
Hello Codeforces!
Yes, it is not a mistake I decided to run the first Div. 4 round: Codeforces Round 640 (Div. 4)! It starts on May/09/2020 17:35 (Moscow time).
The format of the event will be identical to Div. 3 rounds:
I urge participants whose rating is 1400+ not to register new accounts for the purpose of narcissism, but simply to take part unofficially. Please do not spoil the contest to the official participants.
Only trusted participants of the fourth division will be included in the official standings table. This is a forced measure for combating with unsporting behavior. To qualify as a trusted participants of the fourth division, you must:
Regardless of whether you are a trusted participant of the fourth division or not, if your rating is less than 1400 (or you are a newcomer/unrated), then the round will be rated for you.
Please, read some of my thoughts about the problems of this round:
We are just starting, so the complexity of the problems may deviate somewhere from your or my expectations. Wait and see.
The first "thank you" is sent to antontrygubO_o, who helped with the review and selection of problems.
Many thanks to the testers: pashka, 300iq, vovuh, Golovanov399, spookywooky, kocko, Sho, igor_kz, Sho, scott_wu, bfs.07.
I hope you enjoy the problems, and the round will be interesting!
Please, leave in comments your thoughts about exactly this round. If you want to write something about the general idea of Div. 4, then visit this blog post.
UPD: Editorial is published!
Hello Codeforces!
Initially, here was an announcement of the first round for the fourth division. But currently, in comments there is the huge discussion of division 4 rounds in general. Honestly, I read all (almost all) comments.
I decided to replace the text of this post to match the comments better. Also, I'll write one more post separately to discuss problems. And this post will be about division 4 rounds in general.
About Div4 rounds:
I'm not afraid of a queue or servers overload: it is technical challenges and my task is to resolve them. The previous biggest rounds were not overshadowed by technical problems and judging delays, they went well. I see no reasons why something should work much worse in the rounds for Div. 4 (and if it does, then this should be fixed).
I don't think that Div. 3 rounds are too dificult. Actually, they are quite good for beginners. They are noticeably easier than Div. 2. Almost every round trusted participants solve all problems, many participants solve all without one problem. I think in general they are OK.
Now I don't like the idea to run in parallel Div. 3 and Div. 4 rounds (like we do for Div. 1 and Div. 2). Div. 3 rounds are harder to prepare and I don't think we can host them more than once per ~2 weeks. It means that such rounds will not give new contests for newcomers and grays/greens (I think Div. 3 are already interesting rounds for them to take part). But separate Div. 4 rounds will be easier to prepare (even than Div. 3) and probably making them we can offer more contests for low rated participants.
I'd like to repeat: Div. 3 and Div. 4 rounds doesn't affect the rate of Div. 1 and Div. 2 rounds. The coordinators focus only on Div. 1 and Div. 2 rounds. All Div3 (and future, if any, Div4) rounds are prepared without any help from the coordinators.
I do not think that by hosting Div. 4 rounds, we will lower the quality of problems. Now, I don't plan to use absolutely A+B level problems even for the Div. 4. I think problems of level like Div3A-Div3D are good candidates.
Thanks for your attention to this idea!
Hello, Codeforces!
Paul stingray Komkoff is my hero! He found some issues in the network configuration. The most important of them was about flow control auto-negotiation: in case of our network routers the number of dropped packets reduced in times. Thanks!
To be sure that it really helped to fix the issue I ask you to take part in Testing Round 16 (Unrated). It will start on May/07/2020 17:05 (Moscow time). Probably, it will contain 3 easy problems which are not prepared for now (I'll use some old problems, I think). The only reason to host the round is to check the system under a load. It will be an unrated round.
I am upset about what happened with the last round. Once again, I apologize to both the participants and the writer, coordinator and testers. I wrote Monogon about the incident and apologized.
I am sure that the only way to absolutely prevent unrated rounds is just don't host them. And this is not my way. The most popular rounds were hosted without noticeable technical problems. And I'm sure the main records are yet to come. I ask the writers and coordinators to look forward with optimism and try to please us with problems.
Please, join to the testing round. See you!
— Mike.
UPD: Thank you for testing! I think the system worked great. It seems recent reconfiguration improved system performance and stability. We have some rare "Judgement failed" after database update (I'll try to fix them asap).
Sorry about it. Probably, the main reason is a network misconfiguration which leads to degradation of connection speed between some services. Strange things that I didn't change any network settings. Actually, both slow judging and logout issues are sides of the same coin. I asked for the help of the experienced specialist to help me. We are continuing to work on it. No more details at this moment. Sorry again. I'll run testing round before the next round to be sure that everything is OK.
Hello, Codeforces!
Unfortunately, I report that I decided to reschedule this round. I'm afraid that something might go wrong. Some strange database behavior has appeared, which leads to slow operation in completely unexpected places (it never was and should not be). I will work hard to fix it. My recent tests show that this can dramatically increase judging time (and leads to a huge queue). I don't want to risk the efforts of the writer, the coordinator, testers, and your time. Sorry about it, I was trying to fix it for many hours but I need more time. Hope it will be a great round!
Mike.
UPD 1: I temporarily rescheduled it on May, 6. But I'll discuss the date with the writer and coordinator and reschedule it again to the date they want.
UPD 2: Monogon approved that May/06/2020 17:35 (Moscow time) is good new date and time for the round. See you in 3 days!
UPD 3: It seems I've fixed the issue. It turned that it was connected with week ago incident. Now it is 4 AM and time to sleep.
Hi!
As many have noticed, sometimes problem ratings were assigned in a strange way that was not consistent with expectations. For example, ratings for complex problems of Div3 rounds were often overestimated. This was mainly due to the fact that high-ranking unofficial participants did not try such problems. It turned out that despite the high rating of a participant, a problem is not solved by the participant, and this fact raised the rating of the problem. It is not entirely correct to take into account only official participants since ratings for difficult problems are sometimes more accurately determined by unofficial participants.
Somewhere in the comments, I've read that problem ratings are set manually. Of course, this is not so. The process is automated, but I start it manually (I will fix it somehow).
I changed the formulas for calculating problem ratings, now they slightly better correspond to expectations. New problem ratings are already available on the website. I don't think they are perfect (but I hope that they are much better). If somewhere ratings obviously are wrong — it would be great to see such examples in the comments.
Thanks!
UPD 1: Thank you for examples of unexpected problem ratings. I'll try to fix them (I don't think that it is possible to fix all of them without manual work) and return with an update.
UPD 2 [May, 2]: I made another attempt to adjust the coefficients, to take into account some facts differently. The ratings are recalculated again. I carefully went through most of the comments and indicated new ratings. Now it looks a little better. I afraid, there are still some issues with some problems. Try to find them and demonstrate them in the comments. Thanks!
Hi! Yes, I see that the top-rated block and some other features not working, but I don't have the strength to deal with it right now. Also, I didn't fix the ratings because of wrong division cases issues. Since yesterday, I was working on an unexpected behavior of the system on the increased load. A lot has been done. But three hours of sleep in the last two days is too little for me and I need some rest. Tomorrow I'll return to fix the issues and hope to deal with them. What about your quarantine?
Hello, Codeforces.
I hope you wash your hands and feel great.
I added the support of 64-bit g++. If you are using Windows, you can easily install it via our minimalistic package manager PBOX running the command line pbox install msys2-mingw64-9
.
Your solutions are compiled with the command line g++ -static -DONLINE_JUDGE -Wl,--stack=268435456 -O2 -std=c++17 program.cpp
.
Now you can try to use int128 and other 64-bit specific features! In fact, I am slightly worried that the presence of such features may widen the gap between C ++ and other languages. Wait and see.
Currently, support for 64-bit C++ is experimental. For example, I would not be surprised if IO on it works slower in some cases (it is necessary to test!). I invite you to join the testing and experimentations. Share your impressions in the comments!
Name |
---|