Comic : Donald Knuth

Amazing… Found this here

SRM 431 ended in a big confusion !

SRM 431 of Topcoder just finished with a hell lot of discussions and confusion among admins. The problem arose because of the statement of the Division 2 500-pt. Here’s the statement :

You are given a vector <int> X containing the x-coordinates of several points. Each point starts at an infinitely high y-coordinate. Starting with the first point, each point falls down until it is either a distance of R away from a previously fallen point or it reaches y = 0. Each point (after the first point) will start falling only when the previous one stops. Return a vector <double>, where the i-th element is the final y-coordinate of the i-th point.

Found any ambiguity ? Well, there is infact ! Look at the phrase ” from a previously fallen point “. What it signifies is definitely ambiguous. If you’re too proper&strict is English Grammar, you will assume that it signifies any ONE of all the previously fallen points, but if you’re quite an ignorant (like me 🙂 ), you will assume it talks about ONLY the previous point not all the points.

So here came the issue, everyone solved it using their own assumptions and submitted their solutions. Unfortunately, even the given example test cases were so primitive that they were not able to distinguish between the 2 solutions. Finally, what I realized that my assumption of the problem statement was correct and those who assumed otherwise were challenged. So they went to admins, and for 1 hour there was a whole lot of discussion about whether the SRM should be rated or not. Finally, after lots of lobbying and confusion , the admins issued a broadcast message that Division 1 will be rated and their decision about Division 2 will be posted in the forums. Since the Systests were all over and all Division 2 coders were still unrated we all felt that Division 2 is unrated and that our efforts went in vain. But few minutes later, again a broadcast message from the admins – “This time the ratings are really updated ! Please log off and login to see them.🙂“.

So we did, and found our ratings changed ! So now it was clear that no matter what issues are there , the match is rated finally. And then again, admins told us, ” Ratings are updated doesnt mean match is rated. Our decision regarding the issue is yet unclear. If we decide not to rate, we’ll just roll back ur ratings“. So the SRM has ended now, our ratings are updated, but still any moment it can be rolled back to what it was before and this SRM 431 Div2 will be declared a null match.

Lets wait and watch, when their FULLY FINAL decision comes.If they decide to unrate the event, I wish they postpone the event and not just cancel it. They should give another chance to us ! 🙂

For Beginners in [Topcoder]

Things you must know before competing in topcoder.

For Beginners in

Overview

Well, I think there is an urgent need for such an article on topcoder which focuses on those who just joined this great competition arena and are new to the world of online , time-constrained programming contest.

Lots and lots of beginners join topcoder everyday but many of them lose to others as they don’t have sufficient knowledge and “tricks” to help save their time.

Also many of the beginners are used to the old C language and the outdated 8-bit or 16-bit compilers like Turbo C.

However, topcoder works on the upgraded environment and so, many of you find it difficult to implement your algorithms by using vectors, and STL algorithms in C++ on topcoder.

So this article will mainly focus on the things (including some best “tips and tricks”), one must know before starting to code here so as to successfully challenge other competitors.