Some feedback for September Long 2017

First of all, thank you Codechef for another long challenge. These contests are great. There were a few things i disliked and i would like to point them out. Perhaps others agree with me and it will help improve the quality of the contest even more.

  • Problems were not balanced: 3 easy, 1 medium but apparently having weak test cases (SEACO), another medium, and 5 hard problems. Huge jump between 5 and 6 problems solved.

  • Complex problem statements: WEASELTX. It could have been explained much better with a few more sentences instead of those formulas and Delta signs :). Also WEASELSC problem statement was not clear enough, which i understood from the comments section where some great coders asked for explanation.

  • Too much math in some problems: SEAFUNC and SUMCUBE. I just lost interest after seeing all those formulas honestly.

This is just my humble opinion :).
Have a nice day!


I too agree with you. Even i was surprised to see the successful submissions of SEACO.

For the problems SUMCUBE and SEAFUNC, it took about 5 seconds to realize that i have no chance cracking them, although i used brute force in SUMCUBE for 8 points!


Thanks, we will keep this feedback in mind. From next contests, we have focus on making first 5 problems relatively easier than usual, and remaining ones making a bit harder than usual. All your feedback is well taken, we will make sure to improve it up.

  1. Point 1 is correct. 1 simple and 2 cakewalk problems. I can imagine a lot of ties for those who solved on 3 problems…
  2. That was the exact problem coming in my mind when i red the first few words. That statement took me so long to interpret, that too at last at courtesy of a fellow contestant who I must thank for the explanation. That unnecessary use of that triangle and stuff. Gosh! It took me days to get what that statement went :frowning:
  3. Asking or not asking maths more or not depends on setter and his interests. Some people are really crafty when it comes to making mathematical problems. So I wont say any comments here.
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I don’t mind math in problems, but perhaps try to cover it behind some storyline :). I freak out when i see half the Greek alphabet in the formulas of a problem statement :).


Yes, thats a valid point. Giving away straight formula (much worse, giving away all those symbols which we dont know) is bad.

One of his point was Huge jump between 5 and 6 problems solved.. If you make first 5 easier and last 5 harder, you are just increasing the gap.

What you guys can do is, first 5 should be easy, 1st=cakewalk and 5th= EASY-MEDIUM. The difficulty should gradually increase, not like 5 problems done by 2000 and 6th problem only by 200.


I agree too with the above points.
By the way is there some issue like rejudging etc since the ratings have not been updated yet.

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Use the rating predictor, it’s extremely accurate:


Next time I’ll try to come up with interesting story lines… It’s not that easy XD


Yes, I understand that. But anything will work. Some humor, something related to some issue, or any random story/situation coming to your mind. Problem story is one thing where setter can unleash the writer within :stuck_out_tongue:

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thanks a ton! Awesome scrip!!
Dont have enough credits to upvote :expressionless:

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To me, although I didn’t solve the problem completely, such clear definition of problems are easy to understand and start working than a problem having “Ramayan”, “Mahabharat”, “History”, “Drama”, per se. I found myself nowhere in such questions. I prefer questions that are defined directly. I enjoyed all of the questions in this contest because it was easy to me to understand the problem in just one reading. Well solving a math problem is a different scenario altogether. But at least I understood the problem, to begin with.

For example, in the last month’s contest, I missed STRINGRA, just because the language seemed very cryptic to me and I didn’t understand the problem.


STRINGRA had no “Story” as well, so that example is not actually relevant in “problem should not have a story”. In fact, you have yourself given a counter example, that stating statements mathematically makes it tough to understand.

(I hope you arent saying that “Chef constructed this graph, but then lost the sequence A, as well as all the labels on the graph. So all he has left is a directed graph” is the story there, because plainly there are 3 paragraphs of all mathematical definitions and stuff)

Also you cannot rule out that setter intentionally kept the language tough to raise the bar

PS: My comment is directed towards your statement “start working than a problem having "Ramayan", "Mahabharat", "History", "Drama",” because personally I dont find a little story here and there giving trouble in interpretting the question. Either way, its how the mathematical stuff etc. is put up, which is part of problem statement but not “Story”

I guess the setter tried to describe it mathematically in that String problem but he didn’t put it that clearly. All of the problems in this contest were clear and direct. For example, people complain about the delta symbol here. Actually, the setter just tried to be very direct here as the symbols used are actually used to denote diagonals of Pascal’s and Sierpinski’s triangle. So in a way, it was very clear and also gave some hints.


It was clear to people who know those symbols. I for instance, was literally like “WTF, where did this triangle come from?! What is this triangle?”

To me it was more like " John buys 6 apples, eats 5 of them. How many apples does Smith have?"

I think perhaps it was clear to those who know such symbols and things. I think we are both at a different perspective here, and both of our perspective matter. Ideally the statement should be a middle-way of both the extremes :slight_smile:

I agree. May be there should have been some more examples. Especially, it would help testing our code. That little test case in the WEASELTX problem seemed pretty simple to me as it was passing for every wrong code I try to start with. I tried to solve that problem, in 5 different ways (50) every time though. I was always getting that little test case getting passed (even with wrong code).


Sometimes the setters just decide to be more evil XD . Because considerable efforts need to be put to find such a weak test case which passes many wrong solution.

I don’t understand why so many people seem to be afraid of the challenge problem. There have been instances where you got basically no points at all unless you had a pretty sophisticated solution. But in most long challenges even a pretty naive and simple approach will get you quite a few points. Just have a look at this months editorial for the challenge problem. The solutions presented there ( for 40+ points) would at most fit in the EASY category for the algorithmic problems.