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Another impressive debut for India

Posted by rudreshwar on August 31st, 2016 Filed in Contests View Comments

It might be the last contest of the month, but our LunchTime is the one we anticipate the most, for it brings us the brightest young talent from schools across the globe. There have been many names that we have seen grow as a force to reckon with during the course of our LunchTime contests only and there are many others to look forward to. So, you see, in addition to a great programming battle between the whizz-kids, some exciting problems, and an action packed Saturday evening, there is a lot to look forward to when it comes to our LunchTime contests.

And the August LunchTime 2016 was no exception. With Sergey Kulik, Shah Harshil Ketankumar, and Pawel Kacprzak on the problem setting panel, we were assured of a high-octane contest, with plenty of exciting battle for the top spot. And the competition was not only fierce on the schools rank table; even the general rank table saw a lot of action. Let’s start with the main rank table.

The fight to the top here was between someone who we have seen come through ranks and attain the status of pretty much a legend now, and the established legends of CodeChef rank tables. We are talking about rajat1603, who recently joined Chennai Mathematical Institute and is n more a school student and the likes of anta0, acmonster, uwi and others. We have seen Rajat win a Cook-Off while being in school, so it was not so much of a surprise than a treat to watch. And it always is, when you see someone grow in stature in such a short span of time. Rajat started strongly with ALPHABET, which he solved in the first 5 minutes of the contest, following it up with TREEDIAM in the 26th minute. However, LFSTACK and AVGSHORT troubled him a bit, with AVGSHORT taking maximum submissions for the green tick. As oppose to Rajat, anta0 got all his four problems in four straight submissions, and secured the top spot on the rank table.

The scene on the schools rank table was not all that different either, with nano_ape of Shantou Jinshan High School, battling with the LunchTime debutant shivam312 of Delhi Public School, Rohini. And while nano_ape took six submissions to reach the top, shivam312 showed some great persistence for his three problems and took home the second spot in his debut LunchTime. There were few other names too that caught our attention and to tell you all of them, let us take you to the rank table of our August LunchTime 2016.

We start with the ROW top 10:

  • nano_ape of Shantou Jinshan High School
  • iman_gh of Allameh Helli High Schools
  • na2a of Aktobe Kazakh -Turkish High School
  • kmcode of Omori 7th Junior High School
  • zscoder of Chung Ling High School
  • ruhanhabib39 of Kids Tutorial
  • tasmeemreza of SOS Hermann Gmeiner School and College
  • hloya_ygrt of Club of Young Firefighters, Mozyr
  • phoenix1369 of Don Mills Collegiate Institute
  • thanglegons of Chuyên Hùng Vương

And now the Indian top 10:

  • shivam312 of Delhi Public School, Rohini
  • shreerockz15 of Ryan International School
  • adi19988 of Mount Carmel School
  • torque of Ryan International School, Jaipur
  • swetanjal of La Martiniere for Boys, Calcutta
  • yogesh01 of Delhi Public School, Dwarka
  • geekpradd of Delhi Public School Guwahati
  • vishrutjai of Amity International School, Saket
  • sampritipanda of Sai International School
  • aulene of Delhi Public School, Mathura Road

Kudos, To all our young geniuses on their performance into the contest!

Before we move forward let us give you the final figures from the contest. The numbers from the contest:

  • Total Users: 2110
  • Total Submissions: 9049
  • Number of distinct users with correct submissions: 1910
  • Total users from India: 597
  • Total users not from India: 1513

And now, it’s editorial time. We hope you already have gone through, but with the ACM ICPC 2016 – 2017 season ahead, should you need to polish your strengths and concepts, here they are for you.

  • Editorials – August LunchTime 2016

That brings us to the final segment of the post. We hope you enjoyed it as much as you enjoyed the problems from the contest. If you have anything for us, you know where to reach us.

With that, we will wrap us this post. Thanks for being with us through the post and through the contest. We will soon start publishing the posts from the September contests, so keep reading. And with ACM ICPC 2016 – 2017 starting, we will have many interesting tales to tell and if you have a tale, you can always reach us and we would publish it here.

Till next time, adios.

See you at the contests.

- Rudreshwar
Team CodeChef

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Alice and the Tweedle-Dee and Tweedle-Dum

Posted by rudreshwar on August 26th, 2016 Filed in Contests View Comments

When we sat down for the August Cook-Off 2016, the Rio 2016 Olympics were in their final days, and the Olympics of programming i.e. the ACM ICPC were fast approaching. Everyone was geared up to put their best foot forward, be it the sportsmen competing in Rio, or the young programmers around the world sprinting towards the ACM ICPC 2016 – 2017 regionals. We too were getting into the Olympic spirit and getting right behind our favorite sportsmen and you all, our favorite programmers. While the constant support messages and the eventual cheer went out on the social streams, we had our August Cook-Off 2016 well and ready for you all to come and showcase your brilliance. And it gives us immense pleasure to say that, we weren’t disappointed.

The problems of Alei Reyes presented the participants with a great challenge, which they all embraced. However, the start of the contest was not as expected for many of the early birds. Unlike some of the previous Cook-Offs where it was a green tick galore in the early stages, we saw only 7 of those green ticks in the first 50 submissions into the contest. We got 5 more in the next 50, but by now, the dreaded red cross of WA had taken over the submission table. It made us think if everything was alright with the problems, and it was. Our tester Hasan Jaddouh had done a great job testing the problems leaving nothing to be questioned about. And we could have been happier.

The first problems to have received submissions in the early stages of the contest were ALICE and TWEED. And while TWEED, turned out to be an easy nut to crack, ALICE stood exactly at the opposite end of the difficulty spectrum. How difficult it was? Well, out of the 200 submissions that it got, there only were 3 ACs. While, that might sound a tad too difficult, the other problems were not all that easy as well. We had 35 AC out of 300 submissions for MADHAT, 15 out of 150 for MCKTUR, and 9 out of 100 for QUEHEA.  And with the busy competitive programming season ahead, we think it would have given a good practice ground to everyone who participated in the contest. But we still would like to hear from you, what you thought of the problem set, were they a tad too hard for your taste, or they were just as you like the problems to be.

Now, let us take a stroll through the rank tables to meet our winners:

We start with the ROW top 10:

  • ksun48
  • anta0
  • uwi
  • xellos0
  • al13n
  • iman_gh
  • nafis
  • azukun
  • raveman
  • kostya_by

Now, the Indian top 10:

  • sumeet_varma
  • rajat1603
  • akash4983
  • gvaibhav21
  • anudeep2011
  • sp001
  • nims11
  • satyaki3794
  • vidhan13j07
  • siddharth9820

A big round of applauds to all our winners and to you all for competing in the August Cook-Off 2016.

Now, it’s editorial time. Penned by our omnipresent admin Praveen Dhinwa, the editorials will help you understand your mistakes during the contest if there were any. If there were not, you still might want to have a look at them to better prepare for the upcoming ACM ICPC season.

  • Editorials – August Cook-Off 2016

And that will be all from us here at CodeChef. We hope we were able to cover the contest along with all its highlights. However, if we have missed out on any, feel free to let us know. You can write to us, call us, or send us a message on social streams. We love hearing you guys.

We will come soon with the final tale from the August contest, i.e. the August LunchTime 2016, but till then, keep coding.

See you at the contests.

- Rudreshwar
Team CodeChef

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The magical rise of alladdin

Posted by rudreshwar on August 20th, 2016 Filed in Contests View Comments

With August we go one step closer to a rather packed programming season. For the school students, we have the ZCO/ZIO, which for the college students have the ACM ICPC regionals fast approaching. Now, with so many significant competition lined up, programmers seek every opportunity they can get to test their preparations. And in August Challenge 2016 we presented them with one.

The problem set for August Challenge 2016 was nicely spread on the difficulty spectrum. While Chef and Chocolate made life easier in the contest, Chef and Guard Towers presented a stern test to everyone. However, the participants seemed to be enjoying the problems at both the ends of difficulty level. How do we know that? Well, the number of submissions on each of the problem tells us so.

Now, while the problem set was nicely balanced, the competition on the rank table was pretty unpredictable. The battle between the newcomer alladdin and the seasoned ceilks made up for an exciting battle to witness, with the eventual emergence of anta0, skyfire, and rns4 keeping us all on the edge of our seats. We are sure that the participants would have enjoyed the battle even more. Now, to find out who emerged on top at the end of the contest, let us take you through that rank table to meet all our winners.

First, the girls:

  • taube

Now, the ROW top 10:

  • ceilks
  • alladdin
  • anta0
  • skyfire
  • rns4
  • r_64
  • chemthan
  • gomelfk
  • argos
  • min_25

Now, the Indian top 20:

  • pranet
  • apoorv_kulsh
  • mustafa1sms2_3
  • anudeep2011
  • nik1234
  • arjunsanjeev7
  • satishrdd
  • wodahs_cc
  • nims11
  • jc11
  • likecs
  • vedaanta
  • k_sudharsan
  • samarth_1996
  • codeextractor
  • saisumit
  • dudechandan123
  • paramsingh
  • s4shyam95
  • vsp4

Now, we move to schools:

ROW Top 5:

  • sslotin
  • demon1999
  • petukhovsky
  • perchema
  • enchom

Indian top 5:

  • arpanb8
  • anupam_datta
  • shariquemohd
  • swetanjal
  • additya1998
  • dev127
  • iceknight1093
  • gamechanger34
  • hello_231

And finally we move towards the special achievers category with users having highest scores for the challenge problem, other than the winners:

First the ROW top 3:

  • stonefeang
  • ethanjimenez
  • catalint

Now, the Indian top 3:

  • sinhashubham95
  • manish05
  • chinmay2

A huge round of applauds to all our winners and to everyone who took part in the contest. Now, before we move forward, let us give you the final stats for the contest.

  • Total Users: 7173
  • Total Submissions: 89401
  • Number of distinct users with correct submissions: 6472
  • Total users from India: 2290
  • Total users not from India: 4883

And finally, let us take you to the editorials for the contest.

  • Editorials – August Challenge 2016

We hope you enjoyed the contest. And before we put full stop on this tale of August Challenge 2016, let us thank our problem setters Vitalij Kozhukhivskij, Dmytro Berezin, Vasya Antoniuk, Nazarbek Altybay, Rishabh Jain, Kevin Charles Atienza, Shah Harshil Ketankumar, Snigdha Chandan, and Misha Chorniy, our tester Sergey Kulik and the entire panel for creating such a crunchy contest.

That will be all from us. We will soon come back with the stories from the two remaining contests from August. Till then, keep coding and do let us know your thoughts on the contest, the post, or just anything in general.

See you at the contests.

- Rudreshwar

Team CodeChef

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Migration of CodeChef Judge to new servers

Posted by rudreshwar on August 9th, 2016 Filed in Announcement View Comments

SPOJ will be migrating CodeChef Judge to new servers today at 21:30(IST). This will be a quick migration and we will require a submission downtime of 15 mins. We will stop submissions after 21:30 for 15 minutes.

SPOJ will also be moving away from their current server and ISP, to a new server room and cloud. This will not affect the workings of the site in anyway.

Here’s everything you need to know about the entire migration.

  • You will not be able to make submissions into the ongoing August Challenge 2016 for 15 minutes starting 21:30 IST on 9th August 2016 to 21:45 IST on 9th August 2016.

  • The new judge servers are around 30-32% faster than the previous ones, hence, there will be some inconsistency in the execution time for the submissions made after the migration. However, you do not have to worry about the inconsistency as we will be re-judging all the submissions that ran on the old server at the end of August Challenge 2016.

That will be all for us. Should you have any questions or concerns, feel free to get in touch with us.

Rudreshwar,
Team CodeChef

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Yet another triumphant performance rajat1603

Posted by rudreshwar on August 5th, 2016 Filed in Contests View Comments

July perhaps was the best month in the first half of the year. We started the month on 1st of July with July Challenge 2016, followed by the SnackDown 2016 Finals, Cook-Off, and finally everything culminating on the July LunchTime 2016 on the 31st July, 2016. In between there were many other challenges spread here and there, and we are sure you would have enjoyed each one of them. Now, we have already told the tales from the Challenge and Cook-Off, so it’s time now to revisit the LunchTime. So, shall we?

Created by an all Indian and rather young problem setting panel featuring Praveen Dhinwa, Animesh Fatehpuria, and Pushkar Mishra in company with our translation team including Hu Zecong, VNOI Team, and Vasya Antoniuk, the July LunchTime 2016 was all set to give an exciting farewell to July with its four fiery problems. That is not to say that they weren’t fun. With the names like Drumpf for President! and So Close Yet So Far the problems caught immediate attention of the participants, with the former getting the most of it. True to its name, So Close Yet So Far proved to be a tough nut to crack, with only 12 submissions out of the 900 on it getting the sweet green tick of happiness.

Now, our LunchTime contests have been a smooth affair, just like a flag-to-flag race. And we can say that for most of them. However, it wasn’t the case with July LunchTime 2016. However, the issue this time, was the time limit of CLOSEFAR, which was a tad on the higher side. It resulted in submissions taking longer than expected to execute and consequently the prolonged delay in getting the results for the submissions. As a result, we had to change the time limit for the problem twice, during the contest and had to extend the contest by 1 hour. So, the participants got 1 more hour to play with the problems.

All those issues had no effect on the proceedings on the rank table though. For the very first time an Indian school student was emerging atop the global rank table. And it was rajat1603. No surprises there. rajat1603 has gone from strength to strength with every passing contest and it was just one of his vintage performances. The other LunchTime legends including aktl, fleimgruber, and vladik were all present right at the top of the rank table. But with a margin of 50 points rajat1603 took home the July LunchTime 2016.

Who else stood where? Lets find it out through our rank list.

First, we have ROW top 10:

  • aktl of Almaty Kazakh – Turkish High School
  • na2a of Aktobe Kazakh -Turkish High School
  • fleimgruber of Höhere technische Bundeslehranstalt Leonding Limesstraße 12-14 Leonding
  • vladik of Club of Young Firefighters, Mozyr
  • sanroylozan of Debreceni Fazekas Mihály Gimnázium
  • kmcode of Omori 7th Junior High School
  • iman_gh of Allameh Helli High Schools
  • rubabredwan of Rajshahi University School
  • nurbakhyt of Almaty Kazakh – Turkish High School
  • gandook of Allameh Helli High Schools

Now, the Indian top 10:

  • rajat1603 of Delhi Public School, Dwarka
  • arpanb8 of DAV Model School
  • sidhant007 of Delhi Public School, Dwarka
  • sampritipanda of Sai International School
  • anupam_datta of DAV Model School
  • swetanjal of La Martiniere for Boys, Calcutta
  • rohitkv77 of Army Public School, Dighi Pune
  • xrisk of Delhi Public School, Ruby Park
  • AnonymousBunny of Chandannagar Banga Vidyalaya
  • sankushgupta99 of Delhi Public School R.K. Puram

After the rank list let’s have a walk through the editorials, which we are sure you must have enjoyed as much as the problems. So, here they are once again for you:

  • Editorials – July LunchTime 2016

And that will be it, from the July LunchTime 2016. We now move towards August contests and will try and serve them soon.

Till then, do let us know your thoughts on the problems, the contest, and this post. You can send them to us at feedback@codechef.com or can post them straight on the comment section below. We love reading them all.

That will be all from us for now.

See you at the contests.

- Rudreshwar
Team CodeChef

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Lectures from Indian Programming Camp 2016

Posted by rudreshwar on August 3rd, 2016 Filed in Events, Tutorials View Comments

Here are all the video lectures from the Indian Programming Camp 2016.

  1. Biconnectivity By Tanuj Khattar
  2. Discrete Fourier Transforms By Kevin Charles Atienza
  3. Chinese Remainder Theorem by Praveen Dhinwa
  4. Posets Mirsky’s Theorem and Dilworth’s Theorem By Arjun Arul
  5. Path Problem By Akashdeep Nain
  6. Mini–cut By Anudeep Nekkanti
  7. Yate’s Dp, Zeta and Mobius Transforms By Arjun Arul
  8. Algebra By Kevin Charles Atienza
  9. Combinatorics By Kevin Charles Atienza
  10. Number Theory and Mobius Inversions By Kevin Charles Atienza
  11. Dynamic Connectivity Problems and Their Applications By Sergey Kulik
  12. Aho Corasick Algorithm and Applications By Sergey Kulik
  13. Geometry and Number Theory By Kevin Charles Atienza
  14. Merge Sort Tree and Persistence in Data Structures By Sergey Kulik
  15. Square Root Decompositions By Sergey Kulik

Enjoy the lectures and share them among your friends and families.

Rudreshwar
Team CodeChef

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