acm regional coimbatore problems a -how to solve

Let's talk about algorithms!

Moderator: Board moderators

Post Reply
yogeshgo05
New poster
Posts: 47
Joined: Sun Nov 27, 2005 12:43 pm

acm regional coimbatore problems a -how to solve

Post by yogeshgo05 » Tue Dec 19, 2006 6:12 pm

this problem i know it is bactrackinh but still modulo it in circular way is bit
difficult for me so plz some body tell me how to go about it
here is the link

http://www.amrita.edu/icpc/2006/Problems-Onsite.pdf

asif_rahman0
Experienced poster
Posts: 209
Joined: Sun Jan 16, 2005 6:22 pm

Post by asif_rahman0 » Tue Dec 19, 2006 8:02 pm

First try 524, then i think you will get.

http://acm.uva.es/p/v5/524.html

Can someone tell me why same type of problem comes in another contest?
May be the description of it is different but who solved 524, he/she definitely solve this one.

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Wed Dec 20, 2006 1:09 am

Well I have found four old problems in this regional. Some others are quite similar. May be all problems are old, some of which I don't recognize :).

User avatar
sohel
Guru
Posts: 856
Joined: Thu Jan 30, 2003 5:50 am
Location: New York

hmm

Post by sohel » Thu Dec 21, 2006 10:30 am

I was a contestant at this site and was licking my lips after seeing the names of the problems. But later found that the problems aren't identical.

Problem A - this is similar to 524 of uva but the problem statement was a bit different.

Problem B - there is a uva problem with the same name but the one in coim was harder. You have to print the path and also have to maintain other constraints.

Problem C - this is similar to 10400 - game show math. But the one at coim turned out to be tricky due to faulty judge data.

Problem D - New AFAIK.

Problem E - New AFAIK

Problem F - New AFAIK

Problem G - There is a problem in uva with the same name and description, but the one in coim was much harder. Since we have to consider multiple bombs as opposed to single. And only one team was able to solve it.

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Thu Dec 21, 2006 11:18 am

Problem C:
Turning tricky due to faulty judge data is not a credit of the question setter.

Isn't D Josephus Problem - although not a copy, but exactly same problem probably exists.

Problem F:

//The one below is copied from http://online-judge.uva.es/p/v3/379.html
Given a specific board configuration your program will pick and model a specific move, over and over, until no more moves are available. Your program will then report the sum of the holes that still have pegs in them. At any point during the game there may be more than one possible move available. In such a case always model the move with the target hole of the moving peg as large as possible. If there is more than one move available to the largest possible target hole, then choose from those moves the one with the larger source hole.

//This one is copied from comb site
Given a specific board configuration your program will pick and model a specific move, over and over, until no more moves are available. Your program will then report the number of holes that still have pegs in them and their positions on the board. At any point during the game there may be more than one possible move available. In such a case always model the move with the target hole of the moving peg as large as possible. If there is more than one move available to the largest possible target hole, then choose from those moves the one with the larger source hole.

So they just don't want to write problem statements.

I guess in some case the name is same and in some case the problem name is different. I still think this is a bad way of problem setting and if
they did not ask the author or thanked him in webpage it is also not fair. The other bad thing is they copied problems from the same source (UVa)

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Thu Dec 21, 2006 11:26 am

Problem E:
This problem was so far innocent but now I remember it is:

ACM ICPC World Finals 2002 problem C.

User avatar
shamim
A great helper
Posts: 498
Joined: Mon Dec 30, 2002 10:10 am
Location: Bozeman, Montana, USA

Post by shamim » Thu Dec 21, 2006 11:35 am

Does ACM have any rules regarding problem sets?
Do they have any measures to take actions against copy-pasting problem description with minor change.

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Thu Dec 21, 2006 12:33 pm

I am afraid ICPC has no such rule.

User avatar
shamim
A great helper
Posts: 498
Joined: Mon Dec 30, 2002 10:10 am
Location: Bozeman, Montana, USA

Post by shamim » Fri Dec 22, 2006 10:39 am

Looking at the activities of Coimbatore site, I am reminded of the the problem "It's not a Bug, it's a Feature!".
In that problem, it describes how one bug must be kept to introduce a feature.

Last year, the main problem with Coimbatore site was that, they had vague problem description. They have resolved it this time and have done a good job at it. There were hardly any mistake, but how can there be any if the descriptions themselves have existed for few years now. Copy-Pasting well established problem description means, the descriptions are surely correct.

Another problem present last year was delayed judging reply, mosty due to manual cheking of teams output. This year, there were no delays at all as they have used fully automated contest management software named Mooshak. There were no problems with Mooshak, but the problem setters, oh sorry, problem collectors forgot that in automated judging, the data files must exactly match the descriptions and Mooshak has no way of knowing whether there should be a space or not, it just uses the files it was supplied with, where the file contents contradict the descriptions.

This "pretty much" summarize ACM ICPC 2006 at Coimbatore.

N.B: Hospitality was great with very good accomodations.

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Fri Dec 22, 2006 11:42 am

>>N.B: Hospitality was great with very good accomodations.

Hmm! This reminds me of NCPC 2000, where everyone were busy with decorating the lab, buying new curtains, flower vessels but very few cared about the problemset.
Last edited by shahriar_manzoor on Tue Dec 26, 2006 2:26 pm, edited 4 times in total.

User avatar
vinay
Experienced poster
Posts: 104
Joined: Thu Apr 13, 2006 2:26 pm
Location: India
Contact:

Post by vinay » Sun Dec 24, 2006 1:40 pm

these ppl don't realize that accomodation n hospitality r secondary issues....
unless a gud programing contest is made, these "secondary" issues go in vain... :x
If I will myself do hashing, then who will do coding !!!

User avatar
shamim
A great helper
Posts: 498
Joined: Mon Dec 30, 2002 10:10 am
Location: Bozeman, Montana, USA

Post by shamim » Tue Dec 26, 2006 1:10 pm

I am wondering, is it that difficult to create a problem set. Surely creating a good set is very difficult, but a new set with some easy and moderate problems should not be that tough.

Was it really necessary for them to sink as low as copy pasting problem statement :evil:

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

hmm

Post by shahriar_manzoor » Tue Dec 26, 2006 1:38 pm

Probably they wanted to impress by setting a world class problemset. So they just copied from World Class sources. The Audience people will in general look at the problemset and don't care about judge data and in that sense they were successful to fool people who have less idea about problem archives.

The problem with them is similar to an story of famous writer mark twain (MT) "A man went to MT's house and found that there are many books on his floor. He asked him "why books are on the floor?". MT replied you can collect books by borrowing them and then not returning but shelves cannot be borrowed."

The comb site collected the problems but could not collect the data and hence the result is poor judge data.

User avatar
vinay
Experienced poster
Posts: 104
Joined: Thu Apr 13, 2006 2:26 pm
Location: India
Contact:

Post by vinay » Thu Dec 28, 2006 7:54 pm

i wonder how they managed to even change the test data on the fly :o
For some problem the sample data spoke of something else and what got ACC finally was something entirely different....

Isn't it possible to borrow the questions & test data of old ACM problems officially :lol:
If I will myself do hashing, then who will do coding !!!

shahriar_manzoor
System administrator & Problemsetter
Posts: 399
Joined: Sat Jan 12, 2002 2:00 am

Hmm

Post by shahriar_manzoor » Fri Dec 29, 2006 3:25 am

Only CII live archive gets the data officially from different regional contests. But CII don't lend the data to anyone. The regionals can publish the data to their website but other than that there is no means to get the data.

Post Reply

Return to “Algorithms”