OJ Board

why die i got wrong?
who can help me?

To the problem setter: thanks for wasting an hour of time. If you want to make up some function then don't call it factorial, as it's really confusing to those of us who know that factorial is only defined for 0+.

Come on, turingcomplete.

The title is so clear that it play a trick on us.

Didn't you think for a while why it said that " You must be kidding."?

Why WA?

[cpp]#include <iostream.h>
typedef unsigned long long ULLT;

int main() {
const ULLT UNDER = 10000LL, OVER = 6227020800LL;
ULLT limit, fact, i;

while (cin >> limit) {
fact = 1;
for (i = 1; i <= limit; i++) {
fact *= i;
if (fact > OVER) {
cout << "Overflow!\n";
break;
}
}

if (fact <= OVER) {
if (fact < UNDER)
cout << "Underflow!\n";
else
cout << fact << '\n';
}
}

return 0;
}[/cpp]

The problem doesn't state the minimum input, so you must handle negative factorial, like : -1!, -2!, -3!, ...
To find the answer of that problem, just simulate this formula :
(n-1) ! = n ! / n

Good Luck !

For negative numbers it's always underflow or overflow (depends on whether the number is even or odd).

This problem is completely stupid (mathematically incorrect), as you can read on this thread:

http://acm.uva.es/board/viewtopic.php?t=803

You can start flaming me for posting the "solution" here, I don't care... People shouldn't be supposed to guess, only to think about logical things.

How if the input is :
Input :
-1
-2
-3

Ouput:
Overflow
Underflow
Overflow

Is This Right ?
Regards,
RED SCORPION

Yes, I Got AC,
when it is a negative number, I look if it is EVEN,
then the output should be Underflow!, else if
it is ODD then the output should be Overflow!

Thanks,
RED SCORPION

Yes, you're right, Red Scorpion.
And that pattern will repeat again and again (for negative factorial).
However, I still think that negative factorial is undefined.

I can't understand how to calculate factorial of negative numbers...if u put n=0 in the formula (n-1)!=n!/n, u get
-1!=0!/0...how is this possible?

pls give some explanation of the process how negative even numbers get Underflow! and odd numbers get Overflow!...


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Razib
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Our lives improve only when we take chances - and the first and most
difficult risk we can take is to be honest with ourselves.[/quote]

Yes! no doubt about it!
One of the most stupid problem it is!
As far i know acm is for updating our brain.
Not for damage our topic's with bad theory
just to make a problem ubsolved

Hisoka and razibcse, you do not have to use any formula to calculate factorial of negative numbers. Jus print "Overflow!" if the number is odd, or "Underflow!" if the number is even.

Good luc

I get WA.
I think the problem is :

• It used to contain the correct algorithm, but I deleted.

Can anyone help me?

Eric: You do Pascal, don't you? PM me your code, and I'll have a look.

I get Accepted now. Thanks Joey.
It is really a careless mistake.