Coming to July Cook-Off 2016, we were a bit relaxed and rejuvenated. We had just wrapped SnackDown 2016 amid great joy and fervor. The big SnackDown 2016 Final was behind us and life was taking its sweet time to return to routine. Thanks to a couple of week’s gap between the July Challenge 2016, we had the luxury to afford that time. So, we spent some time wrapping up the post SnackDown work and some to get the July Cook-Off 2016 ready for you. Thanks to the awesome problem setting panel featuring Misha Chorniy, Pushkar Mishra, and Karan Aggarwal as the setter, tester, and editorialist respectively, Praveen Dhinwa, the contest admin, and our team of Translators Hu Zecong (Mandarin), Team VNOI (Vietnamese), and Sergey Kulik (Russian), we did not have too much to do.
The problems for the contest were evenly spread across the difficulty spectrum, which means that there was something for everyone into the contest. While Chef and Proportion required users to help the chef in figuring out some proportion, the Chef and Sort asked them to find the expected value of findSwaps function. And while a majority of participants had success with the proportions, finding the expected value of findSwaps function kept them on the edge of their seats.
While the aforementioned two problems were on the contrasting ends of the spectrum with Chef and Proportion being the easiest of them all, we did have Chef and Numbers, Chef and Land, and Chef and Array making life a little easier for the participants. And we think everyone enjoyed them too. At least that’s what close to 10K submissions in 2.5 hours duration of contest suggests. However, we would like to hear your thoughts on the problems, how did you find them? Do let us know in the comments section.
With everyone enjoying the problems, the attention now moved to the rank table. After the blistering performance from rajat1603 in June Cook-Off 2016, we were excited to see what July Cook-Off 2016 has in store for us. Thanks to the debutant ikatanic and um_nik.
While ikatanic was making a return to CodeChef after a prolonged absence, for um_nik, it was the very first contest. However, it’s worth mentioning that it was the first Cook-Off for both of them, so, it’s safe to call them Cook-Off debutants. And what a debut it was. Emerging atop the mmaxio, raveman, al13n, xellos0, and the likes certainly isn’t an easy feat to achieve. And after what we have seen in July Cook-Off, we can’t wait to see them repeat in many of our contests. We think this was one of the best debuts in our Cook-Off’s. If you know of any others, do let us know in the comments section.
With that let’s have a look at the rank table to see who all accompanied our dynamic debutants.
We start with ROW top 10:
And now the Indian top 5:
While the ROW rank list had some big debuts, the Indian rank table to presented a beautiful sight with anudeep2011, djdolls, and rajat1603 occupying the podium. Those are the names that we have been hearing for a long time and certainly will be hearing a lot in the years to come.
And on that beautiful note, let’s move towards the final segment of the post. It’s time for the editorials.
With that, we would like to take your leave for now. We hope you enjoyed the post and that we have been able to cover most of the highlights for the contest. However, if you still think that we have missed any, feel free to let us know through your comments, emails, or through any mode you like. You know how to reach us.
Until next time, keep coding.
See you at the contests.
Lecture 1: Sqrt decomposition, By Sergey Kulik
Lecture 2: Dynamic connectivity problems and their applications, By Sergey Kulik
Lecture 3: Chinese Remainder Theorem, By Praveen Dhinwa
Lecture 4: Introduction of Algebra, By Kevin Charles Atienza
Slides can be found here
Lecture 5: Mobius inversion and related sums, By Kevin Charles Atienza
Slides can be found here
Lecture 1: Aho Corasick algorithm and its applications, By Sergey Kulik
Lecture 2: Biconnectivity and Applications, By Tanuj Khattar
Material can be found at https://tanujkhattar.wordpress.com/2016/01/10/the-bridge-tree-of-a-graph/
Problems to solve:
Lecture 3: Combinatorics, By Kevin Charles Atienza
Slides can be found here
Lecture 4: Geometry, By Kevin Charles Atienza
Slides can be found here
Lecture 5: Finding maximum length anti chains in partially ordered sets, By Arjun Arul
It was pouring outside when we sat for our July Challenge 2016. The monsoon had arrived in its full glory. With a cup of coffee in hands and eyes set on the racing raindrops on the windows, we were all set for an exciting start to July. The build up for July Challenge 2016 could not have been better, with two straight months of programming action in different online rounds of SnackDown leading to the big onsite finale concealed during the course of July Challenge 2016. So, amid the rush of making arrangements for the teams arriving for the onsite finale, and the rush for a cover under the rains, the July Challenge 2016 started.
The problem set prepared by Egor Bobyk, Vasya Antoniuk, Dmytro Berezin, Andrii Omelianenko, Sergey Kulik, Le Mike, Praveen Dhinwa, Misha Chorniy, Kevin Charles Atienza, and Praveen Dhinwa was up for the munching at 15:00 Hrs on 1st July 2016. This was the final competition for the teams travelling to SnackDown Finale to try their hands on, while for others, it was the first long challenge for the new academic calendar. Everyone wanted to get it right.
In typical long challenge fashion, there was not a flurry of submissions coming in right from the start. There was a sense of calmness about the way the submissions were being made into the contest. Every problem was dealt with care and there was no rush to get as many problems as possible in the quickest time. As a matter of fact, most of the users stayed with the popular problems including POLYEVAL and EGRANDR, both of which saw a huge number of submissions. Among the other popular problems were CHEFTET, CHEFARC, and CHEFARC all of which saw in excess of 1K submissions during the 10-day duration of the contest.
While the increase in the submission counter was gradual and steady, the rank list too had a calmness about it, with very little to no change in the names appearing on the rank table. Ceilks, who started his contest with an AC on POLYEVAL in his first attempt, continued his impressive performance slowly but steadily bagging all 10 problems from the contest. Not too far behind ceilks were skyfire, rns4, xellos0, and mrip. They all too solved all the 10 problems. On the Indian rank table, though, there were some new names shaking things up. While jtnydv25, caught our attention by securing the top slot on the rank table, there were many other impressive performances. arjunsanjeev7, manish05, n1t1n_153012, manujain are just a few of the many names that deserve special mention and are the ones to watch out for in future contests as well.
They, and many other names like them were all shining brightly on our July Challenge 2016 rank list. And here they are for you all:
We start with the girls, and we only have 1 entry in that table. So, give a big round of applauds for:
And now the boys and we start with ROW top 10:
The Indian top 20:
Now, we move towards the special achievers with users having highest scores for challenge problem outside the winners. And this time, we had an interesting situation with this category with many users having the same score outside the winners. So, the prize goes to only the first one outside the winners’ category, both from ROW as well as India.
And now for the final category, we have our young champs from schools.
ROW top 5 School students:
Indian Top 5 school students:
That will be for the rank list from July Challenge 2016. A huge round of applauds for all our winners and for everyone who participated in the contest and made it a success.
Now let us give you the editorials for July Challenge 2016.
And with that, it’s time to draw curtains on this long pending July Challenge 2016 post and move quickly towards the remaining two tales from July. We will try to be quick with them and will post them soon.
Till then, keep coding and keep sending us your feedback, suggestions, or just a gentle banter at email@example.com.
That will be all for now, see you at the contests.
Lecture 1 : Persistence segment tree with its applications and merge sort tree. By Sergey Kulik.
Lecture 2: Fast Fourier Transform and its applications. By Kevin Charles Atienza.
Lecture 3: Max flow with its applications. By Anudeep Nekkanti
List of Problems:
Lecture 4: Zeta Function and its applications to optimizations in dynamic programming. By Arjun Arul.
References for Yate’s DP, Fast Zeta and Mobius transforms
For further reading:
Lecture 5: Centroid decomposition and use of reflections in some combinatorial problems. By Akashdeep Nain
Please check the following link for an amazing reference about the concept and related problems on Centroid Decomposition https://threads-iiith.quora.com/Centroid-Decomposition-of-a-Tree
The June LunchTime 2016 and the June Cook-off 2016 made up for a busy weekend, right at the very end of the summer vacations. The reason being, their re-scheduling to accommodate the new schedule of SnackDown 2016 Elimination Round. But knowing you guys, we were sure that there won’t be any complaints regarding squeezing two contests in one weekend. And that’s exactly what happened.
The problems of Pavel Sheftelevich were greeted joyously by the participants. And the contest was off to a flyer. The first problem to get an AC was OMWG, which was cracked under a minute by sugim48. The second submission came on LCOLLIS by the rajat1603 and even though it didn’t see the green tick, it certainly sparked the competition by the arrival of heavyweights in the early stages of the competition. Soon, we saw sampritipanda, fauzdar65, xellos0 and many other names that we have been following appear at different stages and at different places o the rank table.
The approaches were different, the tactics were different, however, the ultimate goal here was the same for everyone and that was to take home the June LunchTime 2016. And while there were quite a few impressive performances during the contest, the one that stood above all came from na2a of Aktobe Kazakh -Turkish High School. It took him an hour to bag all four of the problems from the contest and without conceding any penalties. The only problem that kept him busy for a tad longer than others was SQNUMBF. It took him 4 submissions, but na2a finally solved the mystery of Square in numbers. And in doing so, he also claimed the top spot on the rank table.
To know who all accompanied him on the rank table, let us take you through it.
We start with the ROW top 10:
Now, we move towards the Indian top 10:
Congratulations to all the winners!
And now, here are the final stats for June LunchTime 2016:
Finally, the editorials:
With that, we have reached the final segment of the June LunchTime 2016; we hope you enjoyed this curtailed tale as much as you enjoyed the contest. We will come back soon with the stories from the July contests. We surely will.
Till then, keep coding.