Our 66th Lunchtime took place on November 24 and it was a showdown to remember with a major rank list shake-up! Keep reading to read who gained ratings and who lost them in the November Lunchtime.
Leading the pack in Div 1 was uwi, who is presently ranked number 1 in Japan and number 5 globally. Following our 100th Cook-Off, we mentioned in our Contest Recap that uwi was less than a hundred rating points short of a spot in the global top 5. Looks like, uwi took up the challenge and dethroned China’s ACRush to claim the world number 5 spot. But ACRush is a regular in our Long Challenges, stay tuned to see if he makes a comeback next month.
Other notable mentions in Div 1 are zemen from Russia who moved to 5-star status in this competition and rns5 from North Korea who went from 5 stars to 6. natsugiri, also from Japan, rounded out the top 4, all of whom scored 500. rns5 has risen rapidly through the rating system, gaining a whopping 6 stars since joining CodeChef in August this year. He needs just about 182 rating points to join another, rns4 another celebrated Kim Il-sung University student, in the 7-star club.
In Div 2 mzuev from Russia, took the lead going from 2 to 3 stars in the process. Close behind was xuzijian629 from Japan who was participating in a CodeChef contest for the very first time and made a rating jump of 275 points, which is the maximum jump possible! He promises to be a coder to watch out for. Dubai based antrikshh claimed the third spot, with Indonesia’s sidiqha in 4th place. While no Indians made it to the top 10 in Div 1, 4 Indians secured spots in Div 2’s top 10. A huge shoutout to its_ulure, mindjolt, radon12 and shubham698.
School students were well-represented in the November Lunchtime Div 1 with 9 of them earning places in the top 20. The best performers were tmwilliamlin from Taiwan who was at rank 5, farhod_farmon from Tajikistan at rank 7, and Ukraine’s adalbert at rank 8. Div 2’s best performing school students were its_ulure from India at rank 5, arafat_01 from Kazakhstan at rank 9, and fake_here from China at rank 15.
Special mentions go to female coders amina283 from Azerbaijan and mh755628 from Bangladesh, both of whom made it to the Div 1 top 100. In Div 2, it was hui_yin from Hong Kong and India’s own viralivora who reached the top 100.
Joining xuzijian629 on the list of users who made sizeable rating jumps are mzuev from Russia and tyakennikku from China who improved their rating by 233 points each. Indonesian sidiqha enjoyed a rating jump of 209 points while India’s own its_ulure from West Bengal, increased his rating by 201 points.
The highest participation this month came from India, followed by Bangladesh and Ukraine. India’s National Institute of Technology, Kurukshetra and Jaypee Institute of Information Technology had the most participants in this Lunchtime. If you’d like to spread the word about competitive programming in your school or college, start by creating or joining a CodeChef Campus Chapter today.
Probability (PPAP) emerged as the least solved problem of both Divisions with no successful submissions in Div 2 and just 7 in Div 1. Event (EVENT) was the most solved problem of Div 2 with 769 successful submissions out of a total of 5738 while in Div 1, Beats and Pieces (BPS) got 169 successful submissions from a total of 576. Check out the editorials for this Lunchtime’s problems here.
As we conclude this recap, we tip our hats to our problem setting panel:
Setter: Rehim Memmedli (nots0fast)
Tester: AmirReza PoorAkhavan (arpa)
Statement verifier: Jakub Safin (xellos0)
Editorialist: Hussain Kara Fallah (deadwing97)
Translators:
Mandarin Translator: Hu Zecong (huzecong)
Vietnamese Translator: Team VNOI (khanhptnk)
Russian Translator: Fedor Korobeinikov (gomelfk)
Bengali Translator: Mohammad Solaiman (solaimanope)
Hindi Translator: Akash Srivastava (devils_code)
And as always, many thanks to our problem panel admin Hasan Jaddouh (kingofnumbers) whose hard work helped us pull the contest together.
The November Long Challenge was an exciting one and we’re reliving all the contest chaos through our official November Challenge Recap.
Our standout coders this month were ACRush (Div 1) and xhm154 (Div 2), both from China who aced the Long Challenge with scores of 800 each. In the Division 2 category, a notable mention goes to browni3141 from the US who made an ambitious leap from 1 star to 3 stars by securing the 2nd spot with a score of 799.199. Div 2’s 3-star coders zhouzhendong and zhouyuyang had snagged early leads, but while they were ousted from the top spots, they each earned a star and moved to the 4-star club. Interestingly, all of the top 10 participants in Div 2 earned at least a star in this contest, so Div 1 regulars had better watch their backs!
Meanwhile, in Division 1, most of the key players in the top 10 retained their existing status with some notable exceptions. samjia2000 from China and wmoise from the USA, both earned the elusive ticket into the red 7-star club. wmoise is now ranked 8th in the USA and 83rd worldwide, while samjia2000 has a country rank of 16 and a global rank of 75. But as we all know, the contests giveth and the contests taketh away! We hope the new entrants are prepared to fight for their spots! We also had North Korean rns5, the lone coder with the purple band, who battled 6 and 7-star competitors to add that coveted 5th star to his band with a score of 799.686.
Shoutout to our top ranking school students whzzt, peehs_moorhsum and samjia2000 who all secured spots in the Div 1 top 10 with scores of 780 and above. In Div 2, 4 of the top 10 ranked coders were students: xhm154, howarli, zhouzhendong and zhouyuyang. These rising stars will soon be keeping experienced coders on their toes!
Our homegrown coders also found themselves in the top 10 in both Div 1 and 2 categories. yash_chandnani from Jaipur retained his 7 stars and secured the 5th spot in the Div 1 rank list with a score of 799.513. In Div 2, halberdier secured the third place while thefear from Uttarakhand and Kolkata’s rv_619 landed the number 9 and 10 spots respectively.
A whopping 7421 coders increased their ratings in the November Challenge, and 301 Div 2 coders graduated to Div 1 with ab_initio from the USA who made a significant 186 point rating jump while India’s very own coder3101 from Jharkhand earned 176 rating points during the Long Challenge. Female programmers from India made their presence in the competition felt with 4 coders making rating jumps of over 200. Mumbai’s ziggywiggy led the pack with a rating increase of 217. Among school students, cunbidun from Vietnam increased his rating by 233 points while ilionoid from Kolkata, India saw a rating increase of 219. The Div 1 pool just got a lot bigger since 307 coders graduated from Div 2 to Div 1 following the contest. Salute to eriktillema from the Netherlands who earned 228 to make this leap.
As for the problems, “Chef and Difficult Contests” ironically emerged as the most solved problem with 9774 successful submissions while Max Digit Tree and Chef and Equations saw just 17 successful submissions each. You can check out editorials for all the Long Challenge problems here.
We conclude this recap with a big thanks to our problem setting panel:
And an extra special thanks to our problem panel admin, Misha Chorniy (mgch) whose efforts in the Chef’s Kitchen make our monthly contests fun for everyone!
At CodeChef, we take pride in our innovative community that is constantly striving to create a better environment for all of us. In recent times, we received a lot of requests to open up our API so that our users could develop apps that would benefit the entire community and add new functionalities to the CodeChef platform.
Finally, on the 27th of August 2018, we launched our API and held our very first Hackathon – the CodeChef API Hackathon powered by Alibaba Cloud. This hackathon was held in the spirit of innovation; we already knew that our community was enthusiastic about using CodeChef data to create new resources for each other.
It brings us great joy to share with you the wonderful and innovative entries we received for the contest. It was not an easy task choosing between them, especially since we had to add an extra set of resources due to the sheer number of responses that we received, but we’re finally here with the list! Below is a glimpse of some of them. Check out the entries below and let us know what you think!
All the winners will win collective cash prizes worth $2400, internship interview opportunities at CodeChef, t-shirts and more as mentioned on the contest page.
On to the winners!
1) Chef’s Arena (unsigned_joy)
Team Members:
Alfarhan Zahedi (alfarhanzahedi)
Jatin Pandey (jatinpandey)
Chef’s Arena is a web application designed to give programmers a competitive environment while practising problems. It’s a fast and responsive application with many exciting modes of practice to help users perform better in a contest and prepare for prestigious contests like the ICPC.
2) Virtual Contest (poor_villagers)
Team Members:
Hasan (hasan356)
Vishwanath (vishwanath45)
This app lets you play CodeChef contests in a Virtual environment, those who have played virtual contests on Codeforces would be aware of it.
Virtual Contests enables the users to run the past contests in a special mode that would imitate a real competition. It allows users to get the experience of a real contest while competing in a virtual environment.
3) Virtualizer (sd_1998)
Team Members
Heramb Patil (herambpatil98)
Jugal Rawlani (fatherofall)
Virtualizer allows users to run past CodeChef contests in an environment that imitates a real competition. Features like real-time successful submissions help a user to identify the difficulty of questions. Virtualizer also provides a user with their overall global, country and organization rank and many more features.
The developers have also included an option to create a custom contest which would consist of questions of various difficulty based on the analysis of the type of questions attempted by a user. They have currently included all the past LTIME and COOKOFF contest. They will be extending this feature to include past ICPC regional contests.
4) CodeChef Social (chhole_bhature)
Team Members
Tanmay Datta (tanmaydatta)
Haider Ali (scoobybutter)
Features:
Available on both iOS and Android
Friends – Add/remove/update friend sets .
News feed – Content info and friends activity .
Chat – Real time chat with any CodeChef Social user.
Notifications – Reminders and live contest submissions of friends in live contest via push notifications .
Contest list – Contest page with list of problems .
Tags – Get all the tags and all problems under any given tag .
Todos – Add/remove/update todos .
User profile pages – Easy access to profile of any user .
Compare – Compare profiles of any 2 CodeChef users .
Ratings – Access ratings of any user, in any contest type .
Problems – View the problem statements anywhere anytime (rendered perfectly) .
Submissions – View submissions by friends right in your mobile .
5) Chef’s Tools (fmot_a_rthur)
The app makes possible to run virtual participations in CodeChef and test in CodeChef cloud through terminal
6) Chef On Phone (binaryhackers)
Team Members
Pushkar Anand (pushkaranand)
Adith A Danthi (adith_danthi)
The app allows using CodeChef on your phone. Using this app you can see ongoing contests, future contests, contest problems, practice problems, read problem statements and solve the problems in the IDE built-in inside the app. You can also set reminders for upcoming contests. Download the code from the IDE to make submissions on CodeChef. This will help users to use CodeChef while on the move.
7) CodeChef CLI (epic_shit)
Team Members
Mrigank Krishan (mrigank11)
Vishnunarayan K. I. (z3r0_)
A CLI frontend for CodeChef. Everyone who is a programmer will be closer to a terminal than a web browser. The vim people won’t even like a web browser open when they are solving problems. This application aims to fix that. And fix it will it do.
8 ) Chef-CLI (dilbardilbar)
Team Members
Abhey Rana (uselesscoder1)
Mohit Khare (mkfeuhrer)
Chef-CLI is a command line interface which uses CodeChef’s official API. This application is for those who hate graphical applications and love to do everything through the terminal. With features like sample submit and problem recommendation, It is designed to improve the overall productivity of the user.
8 ) Question Tagger (lhash)
Team Members
Soumya (himanish)
Question Tagger is a multipurpose web app that one can use to tag and analyse their questions.
The key features of the web app are as follows:
-Tag questions – you can tag questions for your reference, so that you can practice questions of a particular tag later for improvement.
-Analyse tags – View all questions along with their submission status of the selected tag to gain insights of your ACs(accepted), WAs(wrong answer), TLEs(time limit exceeded), CTEs(compile time errors) and RTEs(run time error).
-Test generator – You can mark questions for improvement and can later create a practice test out of the questions available for improvement.
-View submission status of questions submitted during the mock test
We’re working on how we can make these apps available to the entire community and integrating them with our platform wherever possible. We’d like to thank you all for making our first Hackathon such a success. We’re looking forward to many such events in the future 
Good luck and happy coding!
Team CodeChef
It’s a month of big competitions for CodeChef’s student chefs in school! Cook up a storm and win prizes that range from cash gifts to the chance to represent India at a prestigious global coding event. Whether you’re a newbie in the world of competitive programming or a seasoned programmer, these competitions may be your shot at coding fame and glory!
What is it?
A nationwide competition organized annually by the Indian Association for Research in Computing Science (IARCS). This competition aims to identify school students with outstanding skills in algorithms and computer programming and give them an opportunity to compete on the world stage of the International Olympiad in Informatics (IOI).
What do you have to do?
Start by entering either the Zonal Informatics Olympiad (ZIO) or the Zonal Computing Olympiad (ZCO). The former is a written test that assesses the student’s analytical and computational reasoning while the latter is a programming contest where the student must use a programming language like C, C++, Java or Python.
When is the contest?
ZIO will be held on 18th November, 2018 while ZCO can be attempted on 2nd December, 2018 both at 36 centres across the country.
Till when can you register?
The last date for registration for both ZCO and ZIO is October 31, 2018.
What can you win?
Students who pass the zonal rounds can appear for the INOI, a national level coding competition. INOI winners will get hands-on training at the IOI Training Camp and a select 4 will represent India at the IOI.
Learn more here: www.iarcs.org.in/inoi/
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What is it?
A unique opportunity for school students to compete against college level coders at the ICPC Regionals round.This competition is all about giving tomorrow’s pro coders an early start.
What do you have to do?
Form a team of at most 3 people and register here www.codechef.com/teams/register/ICPCSC18. You must be a school student to participate in ICPC for Schools.
When is the contest?
The online rounds begin on 23rd October 2018. The on-site finals will be held at two locations: at ABV-IIITM Gwalior on the 16th and 17th of December 2018 and at Amritapuri Coimbatore on the 28th and 29th of December 2018.
Till when can you register?
Registrations end on 21 October, 2018
What can you win?
Every team that solves a minimum of one online problem will receive a participation certificate. Top performers at the on-site rounds can take home cash prizes of up to Rs. 20,000.
Learn more here: www.codechef.com/icpc/2019/schools
What is it?
CodeChef’s own flagship programming competition that attracts the best coders from all over the world. Expect 5 online rounds of intense coding culminating in an on-site finale in Mumbai.
What do you have to do?
Register your team (of one or two) using your CodeChef account here www.codechef.com/teams/register/SNCKQL19 and simply solve the problems to code your way to the top!
When is the contest?
The first round scheduled from October 12 – 16. Detailed schedule can be found here: www.codechef.com/snackdown/2019/schedule
Till when can you register?
Registrations end on October 16.
What can you win?
The global winner of the contest can take home $10,000 with special prizes reserved for school students. Not to mention bragging rights and some well-deserved fame and glory!
Learn more about SnackDown 2019 here: www.codechef.com/snackdown/
Student coders, this is your chance to shine!
CodeChef has been serving the competitive programming community for a very long time. Today, incidentally on the occasion of our 72nd Independence Day, we make a digression. We are excited to announce that we have something for our developer community too!
All this while, we have seen many enthusiastic CodeCheffers, taking the pain of scraping the CodeChef website and creating various really cool and useful stuff out of it. This has made us go one step further and provide all our beloved developers and programmers with the power to turn their ideas into reality much more easily.
So here we announce the launch of the CodeChef API Hackathon powered by Alibaba Cloud.
What is CodeChef API?
CodeChef API is an OAuth 2.0 HTTP API, which exposes CodeChef resources and data to the developers. You will get to know all the details about the API once the contest starts.
Why?
There are things that we want to do and cannot do on our own. And, there are things that we do not even know and can be done. This is where the awesome community comes in. We have seen numerous enthusiastic users who scrape our website to build stuff that does wonders.
We believe that the API now opens up new opportunities for our fellow developers from the community, and will help them build useful and relevant apps which can help the growing community.
CodeChef API – The internship project
It started way back in 2015, when two of the community members proposed to us an idea of making a CodeChef Android app and we were so convinced that we immediately wanted them to get started. Yes you read that right, an Android app! We will get to that story some other time.
Soon we realised that it would be much better to have an API first and then build the app. Since then, there have been many changes in our priorities and despite being partly ready to launch the API, we couldn’t give it to you.
Now
We thank Alibaba Cloud, who liked our idea of an API for the community and supported us in being able to bring this API to you. It gives us immense pleasure to let you know that via our First Hackathon, we are presenting you a brand new CodeChef API that you can consume and you can also build your apps and deploy them on the Alibaba cloud.
Interns & Internship
We have always been proud of our interns and always try to have them throughout the year. They are the packets of energy and enthusiasm which fuel the overall work ethics of the team. CodeChef API was one such project and we thank all our interns who have contributed to the project in some way or the other – Vikesh Tiwari (aka vicky), Shivam Khandelwal (aka skbly), Prabhat Awasthi (aka hacker_ratty) and Shivangi Gupta (aka shivangi_gupta -_- ). Go, hound them!
And with this, we also extend a chance to grab an internship opportunity to all the users who come up with great ideas and implement them.
Looking forward to it…
Cheers,
Abhijeet
The most awaited flagship global coding competition by CodeChef will unfold the curtains to its onsite round in February next year. After successfully completing its four editions and witnessing participation from over 29K programmers in SnackDown 2017, we can say that SnackDown has come a long way since its inception in 2010.
We have been bombarded with questions by the community who were eagerly wanting to know the dates for SnackDown this year. We are here to put an end to all these speculations. Coming to the answer you’re all looking forward to: the online rounds will kickoff in October 2018 and on-site finals will take place in February 2019. We’ll post the final schedule for SnackDown in September, so watch this space!
Oleg Merkurev of Ural Federal University and Aleksei Daniliuk of NRU Higher School of Economics from Russia raised the trophy of SnackDown and claimed a cash prize of $10,000Till now the final round of SnackDown has been an onsite event hosted in India in the month of June-July. This is also the time of heavy monsoons in major parts of the country. To not let the extreme weather come in our way of hosting a glorious finale on Indian soil we decided to keep it in the month of February of 2019.
Stay tuned for more updates to our facebook page – https://www.facebook.com/CodeChef/
Till then, do let us know your thoughts by writing on the comment section below or you can even write to us at: feedback@codechef.com
Cheers!
Team CodeChef
We are happy to announce ShareChat as our official sponsors of our monthly contests.
ShareChat is a social network for the next billion smartphone users. They have grown organically to 18 million active users and are doubling every 4 months. Currently, their userbase is majorly from India, Sri Lanka, Bangladesh, Nepal, Kuwait, Qatar, UAE, Canada and are expanding at a very rapid pace.
With the volume of users that they are handling comes the challenges of scale. And, that makes them a very exciting technology startup to work for. If you are someone who yearns to be a part of the startup culture and a great technology team then you have another reason to participate in our monthly contests.
ShareChat has been supporting us for a while now, and we hope that together with them we will bring more exciting opportunities for the programming community.
We hope this collaboration will be mutually beneficial and also help the community going forward in multiple ways. Wishing you all the best!
Cheers!
The Chef
What is happening?
In light of the recent discussions in the community over plagiarism charges and how this has affected our users and their ratings, we are taking a few steps to restore order in the universe (and to maintain fairness on our platform). Below, we outline the actions we are taking and the motivations behind them.
What action is being taken?
For users whose ratings have been dropped to zero following plagiarism charges, we are increasing the rating by a maximum of 800. We have also ensured that user is penalized by at least of a rating difference of 750.
Formally, we are increasing the rating of all those users by X, where X = minimum of 800 and (Y-750) and Y = previous rating before dropping their rating to 0. We guarantee that X is non-negative.
Why is this action being taken?
You may have been following the discussions taking place in our community over the issue.
Multiple users whose ratings had dropped to zero following plagiarism charges came to us with the concern that such a massive drop in ratings reduces their incentive to participate in contests.
The second concern was that it would take quite a long time for such users to regain their previous ratings.
Finally, some of the users with zero rating who had performed better than those with much higher ratings were getting less rating increments, which they found demotivating.
We understand that many of you felt that the decision to drop ratings was harsh and hasty. It was also pointed out to us that because the drop was not implemented after every contest, it was essentially unfair and did not give all users a fair chance to regain their ratings. After hearing from you all on the issue and brainstorming with our panel and moderators, we have come to this decision. We believe that it is the best way to address your concerns while maintaining as much fairness as possible.
How will plagiarism cases be handled in the future?
For all the future plagiarism scenarios, with each cheating attempt, we will decrease the rating of the user by 750 points flat (however ensuring that the rating doesn’t become negative). There will be no reconsideration or changes in our rating system to handle users with zero rating. No requests for leniency in this regard will be considered.
Further, we will be handling the cheating cases month by month without making any delays in the penalty.
We understand how much it affects our community when we have to take such actions. There is also a likelihood that many honest users get unnecessarily affected by the actions of a few. Do understand that plagiarism is an issue that deeply affects us all and we are trying our best to come up with new ways of combating it and making our community a better and safer place for all of you. As always, we’re there to listen to your suggestions.
Happy coding!
The Chef
As you all know, Chef loves to dish out new enhancements during his birthday month, and this time, he’s cooked up something special which many of you have been asking for – a Rating Divisions system!
Users are now divided into two Divisions based on their overall CodeChef rating.
All CodeChef contests (Long Challenges, Cook-Offs and LunchTimes) will now have two parallel contests, one for Division 1 and another for Division 2. A user can participate in only the Division that she belongs to.
The Division 2 contest will have some more easier problems, whereas the Division 1 contest will have a few more harder ones. This means that beginners get to practice on more easier problems, whereas the higher rated users will skip some of the easy problems and focus on solving the harder ones. A Win-Win situation, if ever there was one!
The ratings will be calculated only within your own Division, and hence will be a better reflection of your true skill level.
Also, we can now have more External Rated Contests, which will be rated only for Division 2 users. The Chef has also introduced Unofficial Participation, through which Division 1 users can also submit in such contests, but it will not affect their rating.
And last, but not the least, we hope that it will be further motivation for users to improve their performance and get to compete with the elite!
Head over here to know more about this system.
Cheers,
The Chef
Our newest initiative, the CCDSAP was launched with an aim to level the turf by providing students and professionals with an even opportunity to get certified on a skill that is fundamental to computer science. Soon, we were reminded that there was more than one uneven turf.
Though we priced the certification very moderately and are also giving away early bird discounts, since the launch, we have received several requests from students who are unable to afford the certification fee. Our endeavour has always been to provide a level playing field and hence this is the first in a series of steps that we intend to take, making the certification affordable to all the student programmers in the country.
We are happy to announce a 100% Scholarship for the next CCDSAP Exam, the details of which are as under:
Winners of the scholarship will be awarded a free registration for the November 19th Exam.
The participant should currently be studying in a school, college or university in India.
The participant has to get the best rank in her institution in the November 2017 Long Challenge.
The participant has to solve 3 or more problems in the long challenge.
In case of a tie between two participants of the same institution, the participant who achieves the rank earlier may be given a preference. One participant from each institution will be selected.
The participant will have to travel to one of the 9 cities in which the exam is conducted on the 19th of November. The cities are Delhi, Mumbai, Kolkata, Chennai, Pune, Hyderabad, Bangalore, Kanpur and Gandhinagar.
This scholarship is not valid for any other exam date and not transferable to anyone else.
If you intend to avail this scholarship, you need to fill up the form – https://goo.gl/PSwKrJ. Only those who fill up this form will be eligible.
After the publication of results of the November Long Challenge, all the candidates who are eligible for the scholarship will be notified via email on how to avail the scholarship. Those interested will need to fill up a registration form to be sent in the email.
Any applicant found cheating or not abiding by the our Code of Conduct will not be eligible for the scholarship.
If you have any queries, feel free to write to us at help@codechef.com
Cheers,
Anup
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