Test data for problem 2516 Sly Number may be incorrect!

hewei · Post by **hewei** » Tue Jul 15, 2003 4:55 pm

I found out that the test data for problem 2516 Sly Number might be the same as provided by the ACM/ICPC problem archive or something like that. But I think this set of test data for "Sly Number" is incorrect and the only two submitters who got AC on this problem probably printed out the "answer" directly in their code.

I found the problem because I noticed that a program which got AC on ZOJ: http://acm.zju.edu.cn for the same problem received WA on this OJ.

Could the administrator of this web site check this out please?

abiczo · Post by **abiczo** » Tue Jul 15, 2003 8:10 pm

As far as I can remember someone who competed in the regional contest where this problem was originally given said that the judge input might have been wrong. So if the judge data used here is the same as the one that was used in the contest then maybe the admins should take a look at it.

Of course admins must be very busy now with the new server, so hewei, you should ask them to check the judge data a few weeks later.

anupam · Post by **anupam** » Wed Jul 16, 2003 3:02 pm

are the problems of archieve very hard?
have any1 solved some easy problems of it.
If yes, please note some of them...

titid_gede · Post by **titid_gede** » Wed Jul 16, 2003 3:14 pm

some of them are easy.. quite easy.. i cant remember the problems, but you can look my statistics.

regards,
titid

sduval · Post by **sduval** » Tue Oct 07, 2003 4:52 pm

Hi,

I found that output file for pb 2516 was wrong... The input/output files for
this problem seem to be the files I've found at http://www.cs.duke.edu/courses/fall02/c ... /Problems/.
I got AC with simply printing the 15 strings of the ouput file...

Actually, for Q=25, N=19 and A=(0 0 2 2 2 2 2 1 1 2 1 1 0 2 2 1 0 0 0),
the output is "A solution can be found" which is not true.
I've tested every 3^19 sly numbers and check that none of them can be
an inverse sly number for A, modulo Q.

St

hewei · Post by **hewei** » Wed Oct 08, 2003 8:16 am

[quote="sduval"]Hi,

I found that output file for pb 2516 was wrong... The input/output files for
this problem seem to be the files I've found at http://www.cs.duke.edu/courses/fall02/c ... /Problems/.
I got AC with simply printing the 15 strings of the ouput file...

Actually, for Q=25, N=19 and A=(0 0 2 2 2 2 2 1 1 2 1 1 0 2 2 1 0 0 0),
the output is "A solution can be found" which is not true.
I've tested every 3^19 sly numbers and check that none of them can be
an inverse sly number for A, modulo Q.

St

sduval · Post by **sduval** » Wed Oct 08, 2003 12:22 pm

Hi,

The vector we are looking for is a sly number that means each of its
componants are in {0,1,2}... The number of candidats for a given sly
number A is 3^N. But you're right when you say :

As a result, you may find out that for some judge input, your program said
"No!" while the judge data said "Yes!", but if the judge output said "No"
your program would always say "No".

St

hewei · Post by **hewei** » Wed Oct 08, 2003 3:16 pm

I'm sorry, sduval. I also made a mistake and I have corrected my last reply.