10235 - Simply Emirp

DemonCris · Post by **DemonCris** » Mon Feb 25, 2002 11:36 am

Is there any special case ?
I have got lots of WA.

I have consider many numbers as following:
1000 -> 1 not prime
2 -> 2 emirp
...etc

junjieliang · Post by **junjieliang** » Mon Feb 25, 2002 11:43 am

Read the definition for emirp properly. My program gives this output for input 131:

131 is prime.

DemonCris · Post by **DemonCris** » Mon Feb 25, 2002 1:35 pm

Thank you ^^

I got it ...

stanley.cai · Post by **stanley.cai** » Tue Mar 05, 2002 3:09 pm

I have noticed it, but I gets lots of WA.
Does it have some others special input,
just like 00002, 00013?
My program outputs:
2 is prime
131 is prime
....

Alexandru Mosoi · Post by **Alexandru Mosoi** » Tue Mar 05, 2002 3:18 pm

while(scanf("%d", &x) == 1)
{
if(!prime(x)) printf("%d is not prime.n", x);
else
if(!prime(reverse(x)) || x == reverse(x)) printf("%d is prime.n", x);
else printf("%d is emirp.n", x);
}

This is my (main) source code.
Why do I get P.E.?

prime(x) - tests if x is prime
reverse(x) - returns x spelled backwards

cyfra · Post by **cyfra** » Tue Mar 05, 2002 4:04 pm

Hi!

Maybe you will consider this test data...

1 - not prime
2 - prime
3 - prime
4 - not prime
5 - prime
6 - not prime
13 - emirp
31 - emirp
19 - prime
91 - not prime (!)

Look especially at the last test case...

Good Luck...

PS.
Maybe you forgot about a dot or made a mistake while writing the output...
Check this

C8H10N4O2 · Post by **C8H10N4O2** » Wed Mar 06, 2002 4:08 am

I am having the same problem. Does anyone know whether it is a bad test set?

Stefan Pochmann · Post by **Stefan Pochmann** » Wed Mar 06, 2002 5:27 am

Since *everbody* only got a "P.E.", there's definitely something wrong with the judge. I usually don't bother fixing P.E.'s, because most of the time it's not my fault.

C8H10N4O2 · Post by **C8H10N4O2** » Wed Mar 06, 2002 1:38 pm

Everyone gets PE. Can someone from OJ check it out?

JWizard · Post by **JWizard** » Mon Jul 01, 2002 4:24 pm

Hi, I tried all the above test data as well as some of my own, but for some reason I keep getting WA... and I'm pretty sure that my output is well formatted.... any ideas ?

10153EN · Post by **10153EN** » Mon Jul 01, 2002 7:01 pm

Not much idea, as the output is straight-forward, except the full-stop at the end of the line.

Would you post your outputs for N = 1-30 and N = 999970-1000000?

SuperBug! · Post by **SuperBug!** » Mon Jul 01, 2002 7:02 pm

Look the sample outputs!!!!! Does your program puts the end dot? When writing the outputs, be sure not to write the left-leaddings ceros. You could be printing the number as string. When output the solutions, the save way is to handle the numbers as not-string (integer, long integer...) You could have an error in your handling string routine!!!
Bye!

10153EN · Post by **10153EN** » Mon Jul 01, 2002 7:26 pm

I agree with the full-stop in the outputs. But to handle the string? This problem need not to deal with strings, but just prime number calculations.

JWizard · Post by **JWizard** » Mon Jul 01, 2002 7:59 pm

Output:

N=1-30:
Prime: 2, 3, 5, 7, 11, 19, 23, 29
Not prime: 1, 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25,26, 27, 28, 30
Emirp: 13, 17

N=999970-1000000
Not Prime: 999970, 999971, 999972, 999973, 999974, 999975, 999976, 999977, 999978, 999980, 999981, 999982, 999984, 999985, 999986, 999987, 999988, 999989, 999990, 999991, 999992, 999993, 999994, 999995, 999996, 999997, 999998, 999999, 1000000
Prime: 999979
Emirp: 999983

10153EN · Post by **10153EN** » Mon Jul 01, 2002 8:23 pm

Same as mine. I think the problem is of no problem. Finally, would you please copy-and-paste your outputs here so as to give me a look?

I think it's the final thing remaining to check~