After two big contests in September Challenge & Cook-Off, the wait for September LunchTime 2016 seemed like eons. You already know how eager we get when it comes to our LunchTime contests. After all, who wouldn’t want to see the young programmers from schools battling it out on a fine Saturday evening? To notch that all up a bit, we had the registrations going on for the upcoming ACM ICPC 2016 – 2017 India regionals, which meant the competition was already on among the aspiring teams to better each other. It just gave us one more reason to look forward to LunchTime. So, we cleared our Saturday evening calendar and kept it all for September LunchTime 2016.
The problem set for the contest came from Misha Chorniy and was tested by Sergey Kulik, accompanying them on the problem setting panel were Pawel Kacprzak, Praveen Dhinwa, Team VNOI, and Hu Zecong, all donning different roles. For every contest we expect a nicely balanced problem set, however, this time around the problems were on exact opposite ends of the difficulty level. While the easiest of them all Chef and Inequality saw over 900 successful submissions, Chef and Words, which turned to be hardest among the four, saw only 8 submissions. Even the situation for the remaining two was pretty identical with 19 and 9 submissions for Chef and Tree and Chef and Triangles respectively.
On the rank table though, the battle was as fierce as ever. And even the start of the contest was pretty good with plenty of ACs in the first half an hour. Most of them though, were on Chef and Inequality, but that is normal and we have seen in many of our contests where most of the submissions in the early stages of the contest come on one single problem only. The first one to taste the sweet nectar of AC was anta0 and it took him only a minute to get that. Soon to follow him were zscoder, nuip, vladik, iman_gh and many others with their ACs on Chef and Inequality. In the first 5 participants to have received an AC, we had two from schools. So, with that, the battle among the school students was on. No, Indian school student was able to make an appearance in the first 50 submissions into the contest. And that was a tad surprising.
While the absence of Indian school students was a bit surprising, the battle between zscoder, kmcode, and austin990301 made up for that. None of the three however, were able to crack all four problems and that affirmed the tough nature of the problems. And to find out who emerged victorious after battling with the problems till the very end, let us take you to the rank table of our September Challenge 2016.
We start with the ROW top 10:
And now the Indian top 10:
Congratulations to you all on your blistering performance and to everyone who took part in the contest.
Now, we move towards the editorials for the contest and considering the difficult nature of the contest, we presume you all would be eager to munch on them if you have not already. So, let us take you straight to them.
And with that, we are done with all our pending blog posts. We hope you enjoyed them all, even though they were a tad behind their scheduled. We are working on your punctuality and will try and publish all the future posts in a reasonable time, after the contest. So, while we work on our punctuality, you join the ongoing October Challenge 2016 and give your ACM ICPC 2016 – 2017 preparations the final touches.
If you have any queries, concerns, or questions you can always write to us at: feedback@codechef.com
Till next time, adios.
See you at the contests.
- Rudreshwar
Team CodeChef
We were coming from “the” biggest long challenge we’ve ever had. We were excited and pumped by the fact that, this is the first of the two Mega Cook-Offs we will be hosting for the aspiring ACM ICPC 2017 aspirants. All that made up for a rather exciting backdrop for our September Cook-Off 2016 and we were excited to join in the contest. And we are sure you were too. This was all before 9:30 pm IST on September 18th, 2016. When the contest bell rang, there was absolute silence and a sense of urgency among everyone, the participants, the problem setters, and everyone here at CodeChef.
The participants wanted to put every step in the right direction, while the problem setters wanted to see them fight with their problem set, and for us, well, we were just excited to some of the top programming brains battle it out. Not to mention, the fight among the Indian ACM ICPC aspirants to finish in top 50 and be eligible for their ACM ICPC travel reimbursed. So, pretty much everyone joining the contest had an agenda. Of course, it is there in every contest; however, the word “Mega” added a pinch of spice to the overall action. So, let us see how it went for everyone.
Let us start with the problem setters, our setter & editorialist for the contest was Tuấn Anh Trần Đặng, who was accompanied by Kamil Dębowski as the tester and Praveen Dhinwa as the admin for the contest. All those gentlemen have enough experience to understand the requirement of a mega cook-off and they had cooked a nicely balanced and testing problem set for the contest. The different flavors of Vietnamese, Mandarin, and Russian for the problem set came from Team VNOI, Hu Zecong, and Vasya Antoniuk respectively. With the problem setting panel confident and ready to see the fate of their problems, it was up to us to make sure that the contest gets a smooth start. And it got what it deserved, a smooth start with no issues what so ever. It was a small victory, but looking back at some of the disastrous mega cook-offs we have had, we were rather happy with it.
As the contest started, everyone quickly moved to the submissions page to see how the participants were faring against the problems. And viola, what a start it was, we got our first AC on TALAZY. It took only two minutes for lebron to crack it, but he was not alone in doing so. In a matter of second’s dreamoon4, rajat1603, and kefaa joined him with the same problem to their name. As the clock ticked, the number of submissions on TALAZY kept on mounting. And soon, it became apparent that, TALAZY is your gateway to your first AC in the contest. Among the first 200 or more submissions that we got, there were only 3 on TACNTSTR and sadly, they were all WAs. So, if there ever was any hint for the participants joining in the contest for where to start, we guess this was it. And it remained like that for quite some time. But every now and then there will be someone trying their hand on other problems too. Some succeeded straightway, some succeeded after a couple of tries.
In the end, though, we had all the five problems solved with Lazy Jem getting a maximum of 2137 successful submissions while Shortest path queries, turned to be the most troubling one with only 8 successful submissions. And now, let us take you through the rank table to meet our winners.
First ROW top 10:
Now, the Indian top 10:
A big round of applauds for all our winners. We hope you all enjoyed the contest as much as we did setting it up for you.
As for the participant’s eligible for their travel reimbursement for the impending ACM ICPC 2016 – 2017 India regionals, we will be contacting them all separately. Till then keep coding and sharpening your preparation for the regionals.
Let us now, take you to the editorials for the contest. We are sure you would have gone through them all by now, however, if you have not, here they are for you:
They will help you get ready for the busy programming season ahead. And we are sure you would enjoy them.
With that, we arrive at the final segment of the post. We hope you are having a wonderful programming season, with plenty of contests to look forward to. We too have few lined up for you in October, so in anticipation of an exciting October ahead of us, we will put a full stop on this tale of the first mega cook-off of the year 2016 and will see you soon, with yet another exciting tale.
If you have any queries or concerns, you can always write to us at: feedback@codechef.com
See you at the contests.
- Rudreshwar
Team CodeChef
September officially rang the bell for the ACM ICPC 2016 – 2017 season in India. In other parts of the world, though, the regionals were already happening and teams from different universities were moving forward towards the World Finals. In India, the registrations for the regionals had just started and the hunt for the perfect team member was on. Even the closest of friends were subjected to great scrutiny, on their programming skills and how well they can cope up with the pressure. How do we know that? Well, we’ve got informers…. Just kidding, we imagine that’s what must be going on in the hostels during the programming season; but whatever. So, while some were still hunting for the team members, few others had already registered their teams and were busy preparing for the regionals.
A cracking contest with some testing problems was something everyone was looking for. So, we obliged with our September Challenge 2016. There still were two more contests in Cook-Off and LunchTime to follow, but the Long challenge was a great start as it helps the participants solve problems and develop new concepts during the ten day course of the contest. And our problem setters had cooked some really interesting problem set revolving around Chef and his many escapades involving his friends, Spaghetti, Palindromes etc. Now, we are not an expert in problem solving, so we don’t know how much the problems helped you guys in your preparation, but we would like to know form you, how were the problems? Did they satisfy your programming buds? Were they fun to play around? So, do let us know your thoughts on the contest, the problems our problem setters would love to read them.
Now, let’s move towards the contest. The September Challenge 2016 started with 7 problems, as the remaining three needed a tad more sautéing. Or so we thought. The remaining three problems were added in the latter stages of the contest, which meant that for a good period of the contest there were only 7 problems. And to make it fair and to give everyone enough time with the newly added problems, the problem setting panel decided to extend the contest to three more days. While there we were questioned on that decision of ours, a majority of participants were pleased with it. At least that’s what the numbers from the contest suggest. Yes, they were huge. So, huge that they made September Challenge 2016 our biggest ever long challenge. Yay! And it’s only fair that we share those numbers with you, after all, you made them.
So, here they are for you:
Now, the big numbers also mean that the competition on the rank table was fierce, with the likes of ceilks, anta0, alex_2oo8, the latest sensation alladdin and many others all going at full throttle towards the top. While the names atop of the table were catching everybody’s attention, there were few shockers as well. Contrary to popular believe the seasoned campaigners and the popular names like ACRush, anudeep2011, rns4, lebron and few others seemed having a bad day at the office. But that’s just the part of the game, we are sure they will come back strong and will give us many exciting contests in the future. For now, let us have a look at the rank table for September Challenge 2016 and congratulate al the winners on their performance.
As always, we start with the girls:
The ROW top 10:
The Indian Top 20:
The ROW top 5 School Students:
The Indian top 5 School Students:
The ROW top 3 users with highest scores for the challenge problem (outside the winner table):
The Indian top 3 users with highest scores for the challenge problem (outside the winner table):
Congratulations all!
For all those who missed it, and we are sure there are not many of you out there, the editorials for the contest can be found below:
And with that it’s time to switch off the lights on this not-too-long-delayed story of September Challenge 2016, we hope you had a wonderful September and that are ready for the impending ACM ICPC 2016 – 2017 season. We wish you all the very best.
Next time, we meet we will be telling the story from the September Cook-Off 2016, which was the first of the two mega-cook-offs we are hosting this year. So, do keep watching this space. For everything else, you can find us at: feedback@codechef.com
Till next time, adios.
- Rudreshwar
Team CodeChef
Nothing pleases us more than making learning to program fun for you. One such opportunity came our way when we met Vinit at the ACM-ICPC World Finals in Phuket, Thailand. Vinit Shah had given a passionate presentation of his platform called uDebug, which was an unknown entity to us until then.
We instantly liked uDebug as we had been wanting to provide something similar to our users but were unable to take it up. One of the objectives of uDebug is to help you debug your solutions by suggesting input test cases of a problem for which the system will show you the output of a solution that’s been deemed “accepted”. Which certainly makes debugging a lot of fun. For us, it can also serve to strengthen the test cases for problems which may have weak test data. There have been incidents in the past where users have reported weak test cases for our problems but there has been no mechanism to validate and get them added.
We instantly discussed a possible collaboration between CodeChef and uDebug by providing users an interface (https://www.udebug.com/) to challenge the test cases for CodeChef’s problems. It meant that now you will have the power to test any problem of CodeChef against your test cases and if the community agrees with you, you can get them added on CodeChef.
It gives us immense pleasure to announce that you can now try your test cases for CodeChef problems on uDebug.
What it means for you as a user is:
We have added problems from our practice section (excluding the Beginner and Peer section) to uDebug for you to try your test cases on. Feel free to go there and experiment with your test data and debug solutions to those problems that you have not been able to solve.
If your test cases pass and find enough love from the community, they will be added to the problems.
How do I report a weak test case?
If you discover that test cases for a problem on CodeChef is weak, add your suggested (stronger) test cases on uDebug and flag the problem.
If your suggested test cases gets enough up-votes from the community, just send them to us at: udebug@codechef.com
We will add those test cases to the problem.
That’s it.
And as always, there will be a reward waiting for you. What it will be, you will get to know when you report it.
We hope you enjoy playing around on uDebug and we look forward to a long and fruitful collaboration with them.
That will be all from us for now.
Happy Coding!
Regards,
Rudreshwar
It was around three years ago, when our team mate, Suraj, had asked us to implement an automated system of sending goodies. We were struggling to deliver the users their winnings on time and quite a few of them would never reach their intended users. Not responded emails, faulty stale addresses, goodies getting lost in transit and tracking issues; left us hassled. We altered processes, included more checkpoints, reached out to our users, but nothing seemed to work.
Quite naturally, we liked the suggestion. The idea was to switch from a “push the goodie” system to “pull the goodie” one. Let the responsibility of getting a goodie be given to the users. We realised this would solve additional problems too, like the same user getting the same goodie multiple times, by giving her more options of accumulating points and winning something of a higher value.
This year, our growing struggle made us pick this up as a gift to ourselves and our users, as we turned seven. In the summer, with our intern, Raju Varshney, putting his hands up, we finally decided to put an all out effort to get this out. While he took up the coding, the rest of us scampered around to get an exciting new list of goodies prepared. And eventually the new system got ready to be served.
However, one thing at CodeChef is that we are a team full of pranksters! We love playing pranks on each other and we thought this to be a great time to include our users. It was long back that we did something similar and since then we have hardly done anything that grave! And this provided us with the perfect opportunity. It also served us as an experiment.
While we implemented the new system, we also decided to change the goodies to those of no monetary value to be considered as a token of appreciation for the effort put by the users. We wanted to see whether all our users want a goodie of monetary value or is it the winning that matters? We added three fun goodies on the site and kept our fingers crossed to see if one can spend her hard earned laddus against something that wasn’t initially promised – the duck, the cube and the ball.
And what we got was a pleasant surprise! Though we got a lot of criticism on the selection of our new goodies, we did find some of our users placing orders to actually get them! Kudos to them! Though we are removing those dummy goodies, we promise to give these users what they have ordered while reverting their laddus into their accounts. We had loads of fun and we hope that you would not mind this small prank of ours.
With this, we unveil the new goodie system. We have credited all your pending winnings as laddus into your account. Go ahead and check them out and have a look at the new goodies. And order whatever you like. We believe you will like some of them. In case you have any doubts or concerns regarding your laddus, do send us an email to laddus@codechef.com. Do not forget to read our terms and conditions to get more insight into the process and to not be disappointed later. We promise it is a good read.
Cheers,
Anup
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.
On 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:
And now the Indian top 10:
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:
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.
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
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:
Now, the Indian top 10:
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.
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
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:
Now, the ROW top 10:
Now, the Indian top 20:
Now, we move to schools:
ROW Top 5:
Indian top 5:
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:
Now, the Indian top 3:
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.
And finally, let us take you to the editorials for the contest.
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
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
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:
Now, the Indian top 10:
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:
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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