No matter how excited you are about your summer plans or are waiting for summer vacations, the words “I’m bored” inevitably will cross your lips pretty soon. So, what do you do? You look for activities that can sweep away that boredom and bring in a fresh breeze of excitement and joy. If you are a programmer, nothing compares to the excitement of competing in a programming contest. And we had that ready for you in our April Cook-Off 2015 with problem set from Konstantsin Sokol. It was time to sit back, sip your coolers, and have a fun-filled two and half hours of Sunday night. And we’ll tell you the complete story of that night in here. So, keep reading to find out how things unfolded in our COOK57.
The start to the April Cook-off 2015 was not dreamlike and the dreaded server crash came back to haunt us. It was an unpleasant déjà vu for us. However leaving everything behind we got back to the slate and started working on getting the contest up and running. It took us some time, but things resorted and the contest was back live. However, by that time, the damage was done and we found ourselves dumped under numerous queries, suggestions, and feedbacks on handling servers from you wonderful people. We tried to reply all of them, and think that we would have replied to most of them, however, if we missed yours, our apologies. Now, as the contest came back, things started looking pretty once again, and the fun that was missing from our Sunday night came back.
By now, we had lost a lot of precious time and may be some programming enthusiasts as well, so to make up for that, we extended the contest duration by half an hour. And as soon as the contest started, the submissions started pouring in. We saw our first submission inside the two minutes of the contest on EQUALITY from mgch, followed by another accepted on from kyuridenamida, but this time around it was on VCS. And for a significant period the submissions only came on those two problems only. Finally after the initially turbulence, the problems tested by Gedi Zheng were finding the love of the participants. Accompanying Gedi on the problem translation panel was Sergey Kulik, with his Russian translation along with our contest admin Praveen Dhinwa.
As the time went pass the action on the rank table started heating up, with countrymen anta0, uwi, and natsugiri battling it hard to secure the top slots. Not far behind were zxqfl, al13n, djdolls, and notimesea. All those names were constantly changing their positions on the rank tables, making it hard for us to establish the winner till the very last stage of the contest. However, the picture started becoming clear just half an hour before the contest when anta0, zxqfl, and uwi cracked the fifth problem. And to tell you who stood where on the rank tables, let us take you through them.
We start with the top ten participants from rest of the world:
And now the Indian top 5:
Let’s give a big round of applause to all our winners and to everyone who took part in the contest. We hope you had fun.
Here are the final stats for the contest:
Those numbers certainly would have been much higher had we had a smooth start to the contest. But we have identified and rectified the cause for the glitch, and hopefully we should not encounter any such issue. Now, before conclude this post, let us give you the editorials for the contest with the delectable editorials from Miguel Oliviera, we are sure you already would have gone through them to get. But if you have not, here they are for you:
With that we draw curtains on this April Cook-Off 2015 post and move towards the final contest post for the month April, i.e. April LunchTime 2015. If you have any queries or concerns regarding the contest or any concerns feel free to get in touch with us at: email@example.com
You can also call us on: (022) – 30797709
That’ll be all for now. Till next time, adios.
See you all at the contests.
April gets its name from the Latin word “aprit” meaning “to open.” The reference here is towards the opening of season, when the trees and flowers open. However, for the students with exams hovering over their head it is time “to open” their books for the final exams. Busy in preparing for their exams students look for a reason to break free from the everyday routine and dive into something exciting, something that will freshen up their minds, without asking too much from them. And we had just the perfect recipe for that in our April Challenge 2015. The ten day course of the contest allowed students to devour the delectable problem set of Andrii Mostovyi, Jakub Safin, Abhra Dasgupta, Lalit Kundu, Praveen Dhinwa, Vitalij Kozhukhivskij, Vasia Antoniuk, and Pavel Sheftelevich at their leisurely pace. With only 3 participants short of the 7K mark, you can say that they did enjoy the problem. And we will tell you more about it during the course of this (delayed) post. So, let’s start.
The problem set for the contest was tested by Sergey Kulik, who also was the part of our translation panel as Russian translator alongside our Mandarin translator, Gedi Zheng. While the problem setting panel ensured the appetizing problem set, the editorialist Surya Kiran, helped the problem related contest queries with the editorials. And our contest admin Praveen Dhinwa ensured a smooth run for the contest by his key inputs and helping hand when needed. The April Challenge 2015, started with nine problems, as the panel needed some more time to play with the tenth problem to make sure that it is contest ready. However, it wasn’t too long before the tenth problem was served.
While the panel was busy putting the final touches on the tenth problem, we found the participants having enjoying the problems so much that we have four out of the nine problems served initially cracked inside the first fifteen minutes of the contest. Problems BROKPHON, CHEFLCM, FRMQ, and DIVLAND received maximum love from the participants in the early stages, however, we all know which one got the maximum affection. The tenth problem PIANO1 made its appearance after an hour and half into the contest and within half an hour of its addition anta0 & kutengine cracked it in the gap of around 5 minutes. All this and we are still into the first days of the contest. As the day passed, the submissions started growing and the action in the rank tables started heating up.
As we moved into the later stages of the contest, the appearance of biggies like ACRush, kutengine, & scli hinted towards an exciting conclusion to the contest. The scenes on the Indian rank tables were a tad different. While, the names on there were not as celebrated as their global counterparts, we are sure all that will change soon after the after the April Challenge and we will get to see more of itisalways42, deathsurgeon, viv001, vijayarsenal10 and company. Now, to meet all those who made their mark on the rank tables, let us take you through the Indian and rest of the world rank tables.
We start with the top 10 from rest of the world:
Now the Indian top 20:
Now, let’s move towards our special achievers category. We start with the top scorers for challenge problem DIVLAND apart from our winners:
We start with the top three participants from rest of the world:
And now the Indian top three:
Now, we move towards our little geniuses from schools:
We start with the top 5 school students from rest of the world:
And now our Indian top 5:
Let’s give a big round of applause to all our winners and to all our participants for a wonderful contest.
Here are the final stats for the contest:
We hope you had a fun filled April Challenge 2015 and a fruitful exam season. Now, we move to the final segment of the post.
The April Challenge 2015 might have had a brilliant start; however, it was not an altogether smooth ride. There were some missing test cases reported for problems DIVLAND and FRMQ, which were added upon identifying. Although, apart from those missing test cases, we had a rather fun filled contest. Now, before we part ways and move towards the April Cook-off 2015 blog post, let us take you through the editorials for April Challenge. We are sure you already would have gone through them, but if you have not check them below.
That brings us to the final segment of this blog post. If you have any queries or concerns, feel free to write to us at: firstname.lastname@example.org
You can also reach us on phone at: (022) – 30797709
That’ll be all for now. Till next time, adios.
See you all at the contests.
“It was the finale of the ICC Cricket World Cup 2015 that day”, that’s what you would say while referring to our March LunchTime 2015. Set on the World Cup Final Sunday, the March LunchTime 2015 already had his glare of publicity stolen, right from the time the world cup schedule was announced. So, while the teams were preparing to secure their birth on the bus to Melbourne Cricket Ground, our dynamic problem setting duo of Pankaj Jindal and Piyush Kumar was busy cooking up the perfect during-match snack, which was tested and translated to Russian by Sergey Kulik. The remaining course for the big day in editorials and Mandarin translation came from Aman Jain and Gedi Zheng respectively. And that completed the lineup for the day. It was now only up to the participants to come and devour the problem set.
We have waited eagerly for this moment, and it was finally here. We are talking about the finale of the ICC Cricket World Cup 2015; the LunchTime was still a couple of hours from now. So, while we were waiting for the ball to drop on the March LunchTime, we treated ourselves to some initial moments of the finale. However, that treat didn’t last too long, so we came back to the LunchTime and ensured that we too get the perfect start. And our start too was pretty close to perfect. All the four problems became visible after intermittent glitches faced by the users here and there. But it was nothing major and got sorted out pretty soon. After that, came the flurry of submissions and the best thing this time was that the submissions came flowing on all the problems alike. If truth be told, we had submissions on three out of the four problems in the first 20 minutes of the contest. And that start gave us plenty of good signs for the coming three hours.
The first problem to see an accepted submission was CHEFANUP and if you do not know it already let us tell you that the problem had one of our chefs as the lead character. And eventually it became the problem to have received maximum submissions. Along with the submissions we got the first glimpses of our winners too in the early days of the contest. It started with fullpower cracking CHEFANUP, followed by mazeyu, gsxj2014, and mappinator. Although not all of them saw the green tick of happiness for their submissions.
It was quite interesting to see them all compete against each other, especially because except for mazeyu, all three of them are from the same institute and all of them are from China. The fight to the top went till the very last moments of the contest with some serious threat coming from meteora, alexvaleanu, victorwonder, and kmcode. However, just minutes before the final hour of the contest mazeyu cracked all the four problems and made a strong statement to the fellow coders from across the globe, however, it was not too long before gsxj2014, and mappinator bagged them too. With that we had a clear picture of our winners for the LTIME22. And to introduce them to you let us take you through the rank tables:
We start with the non-Indian top ten school students:
Now the Indian top ten school students:
A big round of applause for all our participants! We are sure you would have enjoyed the contest.
With that we enter the final section of this blog post. It has already been quite late for this post to go live, so without stretching it any further let’s take you through the editorials for the March Challenge 2015, to help you get over any small doubt, you might have regarding the problems from the contest. So enjoy them:
The March LunchTime 2015 was dominated by the brilliance of mazeyu and meteora, both of whom successfully paved their spots atop the rank table leaving their competitors behind. However, there were quite a few names on the rank table to watch out for in the coming contest. So, with that in mind, we put an end to this post and move towards the forthcoming April Cook-Off 2015.
We hope you are ready for yet another exciting two and half hour of programming contest. And if you have any queries, doubts or suggestions for the contest kindly do send them our ways at email@example.com we love hearing from you all.
Till next time, adios.
By the time we reach March, the tension of looming examination season starts becoming apparent on students’ face. That’s not to say that the professionals are at ease, they too are burdened with the deadline crunches for the financial year ending. In such a tensed time, any stress buster is welcome and for the programming fanatics, nothing beats the excitement of having a crack at the problems, while the clock ticks away. And with our March Cook-Off 2015 we had all that covered for you. It was your time to switch off from everything that has been keeping you under stress, sit back, and enjoy exciting problem set from Vitaliy Herasymiv. And we hope that you had fun in the contest.
The build up to the March Cook-off might have been overshadowed by the impending exam season. However that had no effect on the anticipation of the participants. It became apparent well within the opening minutes of the contest as the submissions started flowing in a consistent fashion. Although, the problems tested by Istavan Nagy were proving to be tough nuts to crack. We did receive our first submission on DIVGOLD inside the first two minutes of the contest, but it was a WA and was followed by a series of WAs from different users. Thankfully, that did not last long and lebron cracked DIVGOLD. After lebron it was antoniuk1, followed by hellkitsune, and fataleagle who went past DIVGOLD. And despite the low number of accepted submissions on the problem, it remained the favorite of the participants in the early stages of the contest, with few glimpses of STRAB and STRBIT.
As we moved into the contest we started seeing more green ticks and less red crosses, however, it was not until the very last moment when we had all our five problems cracked. Keeping up with the ongoing ICC Cricket world cup excitement, our COOK56 too went all the way down the wire before we had our winners with all five problems under their belt. We know, by now you know them all, but still let’s put our hands together and meet the winners from the rank table.
We start with non-Indian top 10:
And now the Indian top 5:
Congratulations to all the participants for their wonderful performance in the contest. We hope you enjoyed the contest.
Now, the final stats for the contest:
With those numbers and some familiar names on the rank table, the March Cook-Off 2015 concluded leaving behind some pleasing memories for all. The March Cook-Off might have kept you all up late in the night in the ongoing cricket world cup season, but we are sure you would have found it all worthwhile after competing in the contest.
We are sure by now you must have gone through the editorials for the problems that made you pull a hair or two during the contest. But to avoid that in the coming contest let’s go through them once again ahead of the impending April Cook-Off 2015.
With that we now quickly move towards the March LunchTime 2015 and will soon put up the post covering the moments from the contest. Till then, enjoy the March Cook-Off 2015 post.
And if you have anything to say to us, feel free to send it through at firstname.lastname@example.org.
That will be all from us for now.
Till next time, adios.
See you all at the contests.
On the occasion of International Women’s Day on Sunday, March 8, 2015 we decided to honor the achievement and contribution of the women in our community with special prizes for them. And it gives us immense gratification to announce that we saw rather inspiring performances from them. So, it wouldn’t be a hyperbole to say that you might be competing with the next Adele Goldbergs, Grace Hoppers or Ada Lovelace all this time.
While the Women’s Day gave us an opportunity to celebrate the women in programming, the colorful festival of Holi added few more colors to the problem set of Lalit Kundu, Sunny Aggarwal, Fedor Korobeinikov, Snigdha Chandan, Sergey Nagin, Gaoyuan Chen, Praveen Dhinwa, Chandan Boruah, Vasia Antoniuk, and Sergey Kulik. With that decorated problem setting panel, the colorful fest of March Challenge was ready for the serving. The problems were tested contest ready by the CodeChef veteran Hiroto Sekido, who has enough long contests under his belt to know what, keeps them beguiling all through the course. And it became apparent, well within the first few minutes of the contest.
More often than not, it’s the flurry of accepted submissions that opens up our Long Challenges. However, it was different this time around. The initial few submissions were not lucky enough to see the green tick of happiness. However, after a series of WA on SEAPROAR, QCHEF, and SIGNWAVE, the participants found some solace in DEVCLASS, which was the first one of the problems to receive an accepted submission. The deceiving difficulty level of the problem set kept the participants pulling their hairs in hunt of accepted solutions. However, it became a tad easy as we moved into the contest.
The first submission from the women participant came into the latter stages of the contest when taube cracked CNOTE. Soon we had ihere1, and chonp climbing their way up the rank tables by cracking the problems one by one. The more impressive of the two was ihere1, who solved 7 problems on the trot and shared the second place on the rank table with taube. However, when the clock stopped on the March Challenge 2015 it was chonp, sitting atop the rank table.
Now, let us introduce you to all our winners from the March Challenge 2015.
Firstly and rightfully so, let’s honor the women programmer. The top ten women programmers are:
And now let’s meet the gentlemen gracing the non-Indian top 10 table:
Now, the Indian top 20:
Now, we move towards our young friends in schools.
We start with the top five non-Indian school participants:
Time to meet our our Indian top five:
And finally, our special achievers with highest scores for challenge problem EMBED:
The non-Indian top three:
None of our Indian participants were able to crack EMBED, so the goodies for Indian top three scores for the problem goes unclaimed. We do not like that.
A big round of applause to all our winners on their brilliant performance in the contest and to all you wonderful participants for being part of the March Challenge 2015!
The March Challenge 2015 will always hold a special place in our history books, for it gave us the opportunity to celebrate the achievements of women in programming. And we are sure that we will see many more women programmers joining in the community and carving their names among the finest programmers across the globe.
If you have had a tough time battling the problem set, you might want to go through the editorials from Kevin Charles Atienza. They will help you clear your doubts about the problems and help you prepare for many such coming contests on CodeChef. And we are sure you already would have gone through them, but if you have not, let us take you through them.
The April Challenge 2015 is on the door. So without any further details we would conclude this blog post in anticipation of an even more exciting long challenge ahead and many more new names to cheer for. We hope you all are ready for the challenge.
If you have any query or concerns for us, you can always send them our ways at: email@example.com
Or can call us at: (022) – 30797709
See you all at the contests.
Sundays are fun days. You get a day off from the routine and indulge yourself into some fun and exciting stuff. And if you are school kid, it’s all about you. You get your choice of food, movie, and you can do whatever you want to. So, who are we to deviate from the established? We too have the last Sunday of the month reserved for you with our LunchTimes. And we hope you have been enjoying them.
The February LunchTime 2015 was yet another fun Sunday at CodeChef. The contest was set and translated into Russian by Sergey Kulik, which ensured the perfect seasoning of fun and learning during its course. And it was testified by Roman Furko. The editorials for the problem set came from the BalajiGanapathi Senthilnathan and the Mandarin flavors for the problem set came from Minako Kojima. All that took place under the moderation of our contest admin Praveen Dhinwa. Our problem setter made sure that the problems have the perfect balance between a testing and an exciting problem set. And with the looming shadow of exam season in the March, the February LunchTime was a great opportunity for our young friends in school to break out and rejoice in the exhilarating 3 hour of the contest. And they did exactly that as the contest started.
We have seen some quick submissions in our contests, but not many of them have been an AC in the first minute of the contest. And the February LunchTime became one of the rarities in that department. The first one to crack the LUCKFOUR was fataleagle from Don Mills Collegiate Institute. It is worth mentioning that the final submission for the contest also came from fataleagle. Now, that is a job well done. But it was that very first submission from him that set the pleasing Sunday LunchTime rolling. And for the next 3 hour the number of submissions on LUCKFOUR just kept on growing. However, the submissions were not as high as some we have seen in the past. But it was enough to make the competition exciting till the very end.
The second problem to receive large number of submissions was WPROB, which received its first accepted submission in the 16th minute from azukun. Now, while the submissions on the problems were not growing briskly, but within an hour we had all the four problems from the contest solved. And to introduce you to the young programmers who solved them, let us present you our rank list.
First the non-Indian top 10:
And now the Indian top 10:
A big round of applause to for all our wonderful participants and winners, without whom the contest would not have been possible!
The names that adorned both the rank tables comprise of names that have been there before and names that were making their first appearance there, and that gives us immense pleasure. However, the star there is meteora, who by now has become a force to be reckoned. She not only has made a mark on the LunchTimes, but also is fast becoming a frequent visitor on our Cook-Offs and Long Challenge rank tables. And it gives us huge pleasure. We want more and more geniuses from schools to come up and make their senior counterparts work harder to save their places on the rank tables. So, if you think you can do it, pull up your socks and get on to it. And to help you with your preparations we have our editorials to help you understand the best approach towards solving these problems.
So, enjoy these delicious editorials and strengthen your preparation.
With that, it’s now time to move towards the next blog post, which will be served soon after a little garnishing. We hope you have been enjoying the updates from CodeChef’s blog and if you have any feedback, good, bad, or a little banter do send them all at: firstname.lastname@example.org
We now enter the exam season with March. So, All the best! Break A Leg.
Till next time, Sayonara.
We are delighted that we turned Senary this March. All this would not have been possible without the problem setting panel in our kitchen. We are truly thankful to everyone in our kitchen for all those delicious problems, mouth watering editorials and awesome contests. We truly appreciate the efforts that our chefs put behind making this possible.
We are happy to announce that we have revamped the problem setting guidelines. You can read more about it here:
Some highlight of the newly released guidelines:
If you would like to join our kitchen as problem setter or tester or editorialist, you can apply here.
With Love and Regards,
Cook-Offs have always fascinated us. They are short, they are filled with action, and they tend to bring out the best in everyone in their two and half hour. Now, while that’s all the fun part, our Cook-Offs also presents us a stern test for our servers and if we mildly put that, our servers have not enjoyed them as much as we have. The recent being the January Cook-Off 2015. And we all know how that went. Coming on the heels of the disastrous COOK54, the February Cook-off 2015 had a lot riding on it. The joy and excitement that normally isthe prologue for our Cook-Offs was overridden by the appalling memories from the past Cook-off. But, this time around we were ready. We have made the necessary fixes and were hopeful of having a smooth contest. And as the clock hit 9:30 pm on the Sunday night, our haunting memories were taken over by the sheer elation of the smooth start of February Cook-Off 2015. And it’s safe to say now, that we had a wonderful contest and that the days of server crashes are behind us now. However, we are still keeping our fingers crossed.
For February Cook-Off 2015 we had an all Indian problem setting panel featuring Devendra Agarwal, Anudeep Nekkanti, & Amit Pandey as problem setter, tester, editorialist respectively. And, the Mandarin & Russian translations came from Gedi Zheng & Sergey Kulik correspondingly. The proceedings of the contest were ardently administered by our contest admin Praveen Dhinwa. The young problem setters poured all their experience and added a touch of freshness to make sure that the problems of the contest are good enough to not only keep the participants engaged for two and half hour of the contest duration, but also makes them pull their hairs. And that’s exactly what happened in the contest.
The February Cook-Off 2015 started off to a galore of accepted submissions on TRISQ as we saw the 48 out of 50 first submissions in the contest on it. And out of those 48, 47 were accepted. So, let’s just say fitting squares in triangle is not as hard as it sounds. As we moved into the contest the submissions kept pouring in and with accuracy percent of 81.73, TRISQ was the most solved problem. However, the rate of submissions on the remaining problems was not pretty much the same. Making strategy for the World Cup is never easy, and our participants found it just before the world cup. However, there were some smart strategists who managed to find the perfect strategy and cracked the problem. The remaining three problems namely SUBARRAY, FOMBRO, and SPSHORT too proved to be tough nuts to crack. However, none of them remained unsolved. Overall, the problem set was nicely balanced with problems for the learners and pros alike.
While the problem set kept testing the participants, it also made the rank table change frequently and the best thing here was that all the names on the rank tables have been here before and hence it was tough for us to write anyone off till the very end. From fhlasek to uwi the fight was on right from the very first submission to the very last. The fight between lyrically, karolis_kusas and fhlasek turned out to be the fiercest of them all, with fhlasek eventually triumphing them both. Now, to meet the final names on the rank tables, let us take you through them.
First, the non-Indian top 10:
And now, the Indian top 5:
A big round of applause for all the winners, and congratulations to all the participants for a wonderful contest!
Now, let us give you the final stats for the February Cook-Off 2015:
While those numbers brought huge smiles on our face, we are excited to see them go further up and have even bigger & smoother contests.
Now, before we move towards our February LunchTime 2015 blog post, we would like to bring your attention at no 5 of the Indian rank table. We have meteora sitting comfortably at number 5 on a Cook-Off rank table. If that’s to be taken as a sign, the college students will certainly face tough challenge from the young participants in the schools. And we are quite excited about it. We are sure you too are. So, if you are in college, it’s time for you to pull up your socks and if you are in school it’s time to announce your arrival on the big stage in style. So get ready.
To help you prepare for the coming contests, it’s very important to clear every single doubt or query that you might have had in the past. And we know a brilliant way of doing that. It’s our editorials. So, let us serve them for you.
It’s now time to put pen down on this lovely tale of February Cook-Off 2015 and move towards the February LunchTime, which saw the young brilliant minds from schools gearing up to announce their arrival at the global programming platform.
We hope you had a wonderful February Cook-Off and love filled month of February. For any query or love greetings you can always reach us at: email@example.com
Or can give us a call at: (022) – 30797709
That is all for now from CodeChef.
Till next time, adios.
See you all at the contest.
If you have never made one, you will never understand how herculean the task of deciding a team name is. We want our team names to reflect our attitude, to communicate, and at times to leave a legend. Whether it’s the serious doers or the dabblers, no one takes their team names lightly. This is why when you have to register a new one every time you enter a competition, it takes the fire out of it.
So, we have decided to let you use the same team name that you once registered with grave intensity. We are sure you must have started digging deep into the backyard of your memory in search of that one team name that you wish you could reuse or could register. And to find all the teams that you have made till now, all you need to do it go to your profile and click on the list given against “Team List”. So, while you are at it, there are a couple of things more that we want you to make note of.
So, what are you waiting for? Put your team names to work.
Competing in teams is a great way for preparing for the ACM ICPC. Once you form a team, you can keep taking part in many team contests that are hosted on CodeChef by institutions and organisations. You can also host your own team contests for your group of friends or school or college or organisation. It provides a great opportunity for you to elevate the programming culture in your institute. To know more about hosting a contest with CodeChef visit here.
We started the new year with the hope of making the first Cook-Off of this year as the most memorable one. And we did ensure that we get the maximum crowd in for the celebrations. Anudeep Nekkanti was handed over the responsibility of creating the problem set. Who else could have done the job justice? Lalit Kundu, Minako Kojima and Sergey Kulik completed the team.
Not for the reasons that we wanted, the story of January Cook-Off 2015 will still be remembered. For the load that the server could not handle and crashed, many times! This will be the first ever unrated Cook-Off at CodeChef.
The problems of Anudeep Nekannti were much appreciated. To add to that, the problem statements were named after the members of our team at CodeChef. We take this opportunity to express our gratitude to Anudeep for this gesture and an awesome problem set. We feel humbled and sad to have let this problem set down.
When a contest goes wrong, it is you, the users, who suffer. We as organisers share the complete responsibility for this to have happened and apologise to all of you who took part in the contest. We goofed up once again. The biggest sufferers are the problem author and the panel who spend a huge amount of time and effort to bring the problem set to you. We apologise to Anudeep and the entire problem setting panel, including Lalit, Minako, and Sergey for not giving them the steady two and half hours that they needed to have for this deserving problem set. We are sorry.
To be fair to all the participants who put in all their heart and soul trying to access the problems, we are making this Cook-Off unrated. Yes, you will not be rated for the contest and there will not be any winners. And we leave it there.
Now, let us explain on what went down in those seemingly never-ending two and half hours and what have we done to ensure that nothing like that ever crosses our way again.
What was the “Cause”?
We had just launched a new feature to show the accuracy and the count of solutions to “subtask” type problems on the contest page separately. This made us fire some expensive queries, which shot up the load on MySQL. Some indexes were missing and MySQL was hogging more CPU. We did not do any profiling after the launch of this feature. The dogpile effect that occurs at the start if any contest and something that we fought hard to reduce game back in a big way and never let the MySQL server recover. It ensued the site crashed. And the rest you know.
What we did to address it then?
It took us a while to identify this. As soon as we did that, we took down the feature, which although made the site run normally, took a lot more time than we would have wanted. And way more time for the contest to be fair to anyone. We also fix the expensive queries in the mean time. However, it was only a temporary fix and we went straight to the drawing board to find a permanent fix to the problem.
Do you have a permanent fix now?
Well, we have found a fix, now whether it is permanent or not, we will find that out in the upcoming Cook-Offs and other high octane contests in 2015. By the time of writing this blog, we have run many contests including the February Cook-Off, and things seem to be under control. However, to be frank, we have not yet received as much load as we did in the January Cook-Off.
What is the fix?
To start with, we have profiled and fixed all the misbehaving queries to make sure that they do not cause any such trouble. While investigating the cause, we also found that our rate limiter was put off, which contributed significantly to increase the load. We have enabled it again. Also, we took this opportunity to dig hard and identify what can be better fixes to reduce the dog pile effect at the start of our contests and improved the way we were creating our cache as well as locking the cache. So far this has worked and we believe the issue has been fixed.
We know, this is not the first time we have “goofed up” in a Cook-Off and we have tried hard to get things fixed. So, do not get dismayed and keep the problem cracking going. Also, keep sending your love for the chefs at CodeChef. We do need that.
That will be all for our unrated January Cook-Off 2015. We hope it answers your queries regarding the issue during the contest, the ratings or the winnings of the contest. However, if any of you still have it, feel free to write to us at: firstname.lastname@example.org
Till next time, TA-TA
See you at the contests.