333 - Recognizing Good ISBNs

All about problems in Volume 3. If there is a thread about your problem, please use it. If not, create one with its number in the subject.

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ftomi
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Post by ftomi » Wed Jan 23, 2002 11:30 pm

Should I accept the next ISBN?
"------963-19-0853-4-------"
What should I do, if the last line contain only EOF?
Is This 'empty' line "not correct", or is it the end of input?
Thanks!

..
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Post by .. » Thu Jan 24, 2002 7:35 am

Hi,

For most of the problem on online judge,
EOF is the end of input, and should NOT be processed........
Good luck~~

Ivan Golubev
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Post by Ivan Golubev » Thu Jan 24, 2002 12:00 pm

------963-19-0853-4------- is correct.

Process blank line as other lines, i.e. output 'is incorrect' but EOF is always EOF, of course it need not to be handle.

ftomi
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Post by ftomi » Thu Jan 24, 2002 12:42 pm

Thanks!
But in this case, what's wrong in my program?
:roll:

Ivan Golubev
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Post by Ivan Golubev » Thu Jan 24, 2002 2:17 pm

It's difficult to say what's wrong. There were some tricks in this problem (AFAIR):

1. Hyphens can be anywere.
2. The ISBN cannot be less than 10 symbols long (of course, excluding hyphens) but can be more than 10 symbols.
3. There can be leading/trailing spaces and tabs.
4. There can be only one 'X' and it can be only at last position in the ISBN (so, there can be hyphens after 'X').

ftomi
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Post by ftomi » Thu Jan 24, 2002 2:41 pm

Oh, I see!
I've just made it!
Hmm. Tab is space...
I notice it!
Thanks for all!

yatsen
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Post by yatsen » Fri Jan 25, 2002 3:36 am

I thnik 333 is not difficult, but I got WA.
Can anyone tell me what is wrong with my code?
#include <stdio.h>
#include <string.h>
#include <ctype.h>
main()
{
int i,j,k,incorrect,isbn[3000],s1[3000],s2[3000];
char line[3000];
while (scanf("%s",line)==1)
{
incorrect=0;
for (i=0;i<3000;i++) isbn=0;
k=strlen(line);
for (i=0,j=0;i<k;i++)
{
if (line=='-') continue;
if (isdigit(line)) isbn[j++]=line-'0';
else
if (line=='X')
if (j==9) isbn[j++]=10;
else { incorrect=1; break; }
}
if (j!=10) incorrect=1;
else
{
s1[0]=isbn[0];
for (i=1;i<10;i++) s1=s1[i-1]+isbn;
s2[0]=s1[0];
for (i=1;i<10;i++) s2=s2[i-1]+s1;
if (s2[9]%11!=0) incorrect=1;
}

if (incorrect) printf("%s is incorrect.n",line);
else printf("%s is correct.n",line);
}
return 0;
}

ftomi
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Post by ftomi » Fri Jan 25, 2002 11:16 am

the next line wrong, beacause if there is gap between 2 part in line, your program handle it as 2 line.

while (scanf("%s",line)==1)

for example:
This is a wrong line

Your program generate 5 output line instead of 1.

You should use while(gets(line)) and search the start, and the end of the isbn in the line.

yatsen
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Post by yatsen » Tue Jan 29, 2002 3:36 am

After use gets(s) instead of scanf("%s",s), I finally got accept!
Thank you very much!

C8H10N4O2
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Post by C8H10N4O2 » Sun Apr 28, 2002 5:50 am

Can someone tell me what is wrong with this code?
[cpp]
#include <cstdio>
#include <cstring>
#include <cctype>
#include <vector>
#include <algorithm>

using namespace std;

void main()
{
char B[1000],S[500];
bool GoodISBN;
int i,j;
vector<int> ISBN;
while(fgets(B,1000,stdin)!=NULL)
{
GoodISBN=true;
ISBN.clear();
for(i=0;i<strlen(B);i++)
{
if(!isdigit(B)
&&B!=' '
&&B!='-'
&&B!='X'
&&B!='\n'
&&B!='\t')
{
GoodISBN=false;
break;
}
if(isdigit(B))
{
ISBN.push_back(B-'0');
}
if(B=='X')
{
ISBN.push_back(10);
if(ISBN.size()!=10)
{
GoodISBN=false;
break;
}
}
}
if(GoodISBN)
{
if(ISBN.size()!=10)
{
GoodISBN=false;
}
j=0;
for(i=0;i<ISBN.size();i++)
{
j+=ISBN*(10-i);
}
if(j%11!=0)
{
GoodISBN=false;
}
}
strcpy(S,"");
sscanf(B,"%s",S);
if(GoodISBN)
{
printf("%s is correct.\n",S);
}
else
{
printf("%s is incorrect.\n",S);
}
}
}[/cpp]

wyvmak
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Post by wyvmak » Sun Apr 28, 2002 6:05 am

At least, as Ivan said, your code seems can accept more than one X - which is not allowed

C8H10N4O2
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Post by C8H10N4O2 » Sun Apr 28, 2002 3:40 pm

Whenever it sees an 'X', it checks to make sure it is the 10th digit, otherwise it flags the ISBN as bad.

xenon
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333 rejudgement??

Post by xenon » Sat Jul 13, 2002 9:11 am

So I woke up this morning, and found the Judge gave me one less problem solved than my own administration accounted for.
Checked, rechecked and double checked my mail, but no rejudgement notice.
Then compared all the problemnumbers in the Judge's solved-list against my own and discovered 333 was missing!
What is going on? Out of 3429 submissions, only ONE has AC. Can this really be true? And what about a rejudgement notice?

A very sad,
-xenon

Caesum
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Post by Caesum » Sat Jul 13, 2002 10:20 am

I notice that rejudgement notices normally take a few days to arrive

xenon
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Post by xenon » Sat Jul 13, 2002 11:12 am

Hmm.
Did you already dig deeper into the possible change? First inspection shows no change in the problem description. No warning sign with additional notes either, so I guess we're in the dark.
In a file I keep for making statistics, I found that some weeks ago there were some 600 people with AC on this problem. In my opinion it is a little harsh to sweep them all off by a rejudge, since that implicitly means they all misunderstood the problem :-?
But... such is life.

Still crying in the rain,
-xenon

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