Invitation to DUCS Winter Warm-Up 2019

Greetings CodeChef community!

Winter has arrived and 2019 is about to end, what else do you want on such a cold year end than a light-heart programming warmup contest. DUCS Winter Warm-Up 2019 is probably the last contest of 2019 hosted on CodeChef, and more than a contest, it is a kick start for budding programmers and beginners. It is more like an Educational Contest. So, I don’t think there is any better time to start.

I invite you to participate in DUCS Winter Warm-Up 2019. This contest lets you solve 11 problems in 5 hours. The contest is open to all programmers of all ages and skill levels across the world.

I hope you will join your fellow programmers and enjoy solving the contest problems.

Contest Details:

Start Time: 03:00 PM IST (+05:30 GMT), 31st December 2019
End Time: 08:00 PM IST (+05:30 GMT), 31st December 2019
Check your time zone here.

Contest Link:

Registration: You just need to have a CodeChef handle to participate. For all those who are interested and do not have a CodeChef handle, are requested to register in order to participate.

Prizes: 250 CodeChef Laddus each for top 3 overall performers, with which winners can claim cool CodeChef goodies. Know more here.

Good Luck!
Hope to see you participating!
Happy Programming!


waiting for some awesome problems :slight_smile:

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Let the game begin :boom:


good to see . i am excited too. ending year with some code,not a bad idea:grinning:

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Thank you so much everyone for taking part in DUCS Winter Warm-Up 2019.

I had created this contest truly independently and the main motive was to give a kick start to beginners at the last day of 2019. I had intentionally kept all the problems doable for beginners, I know seasoned programmers would have found this contest way too easy but I never wanted to see this as a contest but something educational. The most important thing for me was to make problems in such a way that beginners are able to solve around half or more of the set easily, which surely will boost their confidence and provide them with a good kick start.

Actually after my semester exams got over in mid December, I thought of doing something meaningful for the whole community, that’s when I planned this contest. And it was very hectic for me because I started very very late and from scratch and I was all alone. Also I didn’t want to tell about this contest to my peers at University because it was also a surprise for my seniors at DUCS. The likelihood of my seniors coming to the University during the next semester is very less, so I wanted to give them a surprise before year end and before they go, something that they’ll remember and will stay for long. So I dedicated all of the contest to them. All of the problems are based on my seniors at DUCS and it was a surprise for everyone. It had a lot of internal references, meanings and memories linked for everyone. Also, problem codes were sorted in the order when I met that particular senior.

Also, I tried to give a learning to beginners with each problem. This is what I intended:

DWW19A: Strings can be treated as numbers (which is not so obvious for beginners), something like a palindrome.
DWW19B: Relation between LCM and GCD, and most importantly about overflows and limits (which is one of the most common mistake during the initial days), and smart tricks to handle them like using some basic mathematics, some smart arithmetic tricks and stuff.
DWW19C: Very very basic greedy strategy, counting characters and everything basic with a string.
DWW19D: Prefix sums, binary search, basic sliding window algorithms.
DWW19E: Basic graph traversals (DFS or BFS) on a grid, some mathematical proofs and assertions, modular arithmetic, modular inverse and some basic combinatorics.
DWW19F: Online algorithms and self ordering data structures like priority queues (heaps) and multi-sets (balanced trees).
DWW19G: Online algorithms and some special data structures like indexed set (GNU Policy Based Data Structure) or Segment Tree or Fenwick Tree (Binary Indexed Tree (BIT)) and other such tree based structures for efficiently handling online queries.
DWW19H: Basic counting with strings, integer overflows, and some very basic observations.
DWW19I: Basic GCD trick and mathematics.
DWW19J: Very very basic concepts of Number and Game Theory and Primality test (sieve and binary search for small test set, an overkill but very fast) , observations, factorization.
DWW19K: Real numbers and precision, just wanted beginners to know how to print real numbers during contests.

I just wanted everyone (especially beginners) to learn something before the arrival of 2020 and kick start them, so that they can start off things well in 2020. Also a nice coding warmup for everyone on the last day of 2019 in this cold winter season.

I’m also planning to publish editorials for this contest, so please be patient and allow me a few days, it will take a few days along with University.

I hope you all enjoyed this light heart programming contest!
Happy Programming!


really enjoyed it . if these type of exams occur more frequently on codechef it would be more fun,other experienced guys can collaborate in order to do so.good job bro


I have published detailed editorials for all the problems. So even if you missed out on something, or want to know more about the concepts behind the problems, you should definitely see them. All explanations along with a clean and concise implemented solution have been provided. In my honest opinion, everyone should go through them at least once.

You can find all of them here.

Also, announcements have been made on the contest page. Tags have been added to all the problems and editorials. Editorial links have also been added to all the problems.

Happy Coding!