10683 - The decadary watch

[pipo]

thanks krijger..

well.. i understood the first and second you told.

but.. i didnt understand the third...

what is difference between the third and casting in my code.. ?

what is 'avoiding small rounding error' you said ...

please show me examples about the small rounding error through source code.

thank you...

[krijger]

Code: Select all

#include<stdio.h>
#include<math.h>

int main() {
	for(int i=0;i<100;++i) {
		double val=sqrt(double(i))*sqrt(double(i));
		if(i!=(int)val) printf("%3d: %24.20lf %3d %3d\n",i,val,(int)val,(int)(val+1e-10));
	}
}

Obviously (int)val should be the same as i, but sometimes it isn't. If you use (int)(val+1e-10) everything goes well. Try it, you'll see.
Note that this method is by no means exact. The idea is that if something is only a very little less than a integer number, it was probably a rounding error, so we should use that integer number instead of the one far below it.
Also note that you have the same problem when checking for equality,lower/greater than, etc. Therefore I use this for floating point testing:

Code: Select all

#define ABS(a) ((a)<0)?-(a):(a))
#define EPS 1e-10
inline bool lt(dbl a,dbl b) { return a<b-EPS; }
inline bool le(dbl a,dbl b) { return a<=b+EPS; }
inline bool gt(dbl a,dbl b) { return a>b+EPS; }
inline bool ge(dbl a,dbl b) { return a>=b-EPS; }
inline bool eq(dbl a,dbl b) { return ABS(a-b)<=EPS; }
inline bool ne(dbl a,dbl b) { return ABS(a-b)>EPS; }

(lt=lower than,le=lower equal,gt=greater than,ge=greater equal,eq=equal,ne=not equal)

[pipo]

krijger.. thank you for answer..

i finally got accepted.

its problem is precision you told the second case.

and additionally i got the round error..

it's very interesting of me.

thank you again..

[dust_cover]

Hi can someone tell me what is the problem with my code?
I have read all the topics before but cannot fix it
Moreover i have used all integer type to get over precision error.

Code: Select all

removed after ACC

thnax in advance!

[sakhassan]

Try to use double & floor

Try this input
01000000


ur output is
416667

mine in:
0416667

[dust_cover]

hi Sakhasan,

thnx for your quick reply. I fixed my code & finally got ACC. I am too much grateful to you

[Mushfiqur Rahman]

I tried this problem for many times but got WA. I didn't found my bug.
Anybody help please.

Here is my code.

Code: Select all

Removed after AC.

[Jan]

Try the cases

Input:

Code: Select all

11014944
00114416
16570432

Output:

Code: Select all

4596000
0081500
7063000

Hope these help.

[Mushfiqur Rahman]

Thanks for your cordial help and data set. The bug was in floating division.
I replaced it by integer division and got AC. Can u tell me how can i remove the problem given bellow ?

double temp ;
long a;

temp = 5184/86.4 ; // here temp = 60.000000

a = temp ; // here a will be 59, but why?

[Jan]

It is called precision error. Try reading the following thread
http://online-judge.uva.es/board/viewto ... 5&start=15
Hope it helps.

And don't forget to remove your code.

[Mushfiqur Rahman]

Thanks for the given link. I think it will also help more preson.

[arifcsecu]

not so hard ...Integer Division is sufficient
long int h,m,s,c,tt;

while(gets(ch))
{
h=(ch[0]-'0')*10+(ch[1]-'0');
m=(ch[2]-'0')*10+(ch[3]-'0');
s=(ch[4]-'0')*10+(ch[5]-'0');
c=(ch[6]-'0')*10+(ch[7]-'0');
tt=((h*60+m)*60+s)*100+c;
tt=tt*125/108;

printf("%07ld\n",tt);
}

[plamplam]

Goddamn it.....this thing pissed me off so freaking much....I still don't understand why the following code doesn't get Accepted.
Consider this:

Code: Select all

    for (; ;)
    {
        gets(str);
        if (feof(stdin)) break;
        .....
    }

This gets a straight wrong answer but If I replace it with:

Code: Select all

    while(gets(str))
    {
        ...
    }

It gets Accepted right away...any explanation for this? Thanks in advance.

[Hithrow]

Goddamn it.....this thing pissed me off so freaking much....I still don't understand why the following code doesn't get Accepted.
Consider this:

Code: Select all

    for (; ;)
    {
        gets(str);
        if (feof(stdin)) break;
        .....
    }

This gets a straight wrong answer but If I replace it with:

Code: Select all

    while(gets(str))
    {
        ...
    }

It gets Accepted right away...any explanation for this? Thanks in advance.

I don't know the reason why it is not accepted, but thanks for the code replaced itself. You've helped me a lot! cell phone spy

[plamplam]

Glad to help