10668 - Expanding Rods

All about problems in Volume 106. 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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Jan
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Post by Jan » Fri Apr 06, 2007 1:15 pm

First search your problem. If you find any thread then use it. If no thread is found then and only then you are allowed to open a new thread.

However, check the thread.
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ayeshapakhi
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Post by ayeshapakhi » Fri Apr 06, 2007 1:43 pm

Thanks a lot for help.
i've seen that thread before posting here. There's no testcases.
I can't find any logical error in my code (used bisection and it seems all of my i/o 's are ok) and finally i posted my code in another thread but there's no reply...
so......

thanks.

Jan
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Location: Dhaka, Bangladesh
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Post by Jan » Fri Apr 06, 2007 1:56 pm

Replace

Code: Select all

#define err 1e-10
with

Code: Select all

#define err 1e-13
Hope you get accepted.
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Jan
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Location: Dhaka, Bangladesh
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Post by Jan » Fri Apr 06, 2007 2:00 pm

You have to be patient. If you find no reply (for a long time) then you can post in that thread again, like "Can anyone help?". Actually when we log in, we check the new posts. Thats why we can check your problem again.
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ayeshapakhi
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Post by ayeshapakhi » Fri Apr 06, 2007 4:50 pm

Strange!!
Really it got acc!.........
Infinite thanks for u.

Thanks again.

ayeshapakhi
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Posts: 60
Joined: Sun Apr 16, 2006 7:59 pm

Post by ayeshapakhi » Fri Apr 06, 2007 4:54 pm

Sorry for inconvenience....
Thanks a lot for help.......

gba356
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Post by gba356 » Tue Feb 05, 2008 8:20 am

I've used 1e-15 as my epislon, but the online judge system keeps give me constant WA. Can somebody check my code? I choose Bisection as my algo.

Code: Select all

#include<iostream>
#include<cmath>
#define e ( 1e-15 )
using namespace std;
    double L,n,C,S,S2,theta,r;
    
inline double ABS( double x )
{
    return( x>0 ? x : -x );
}    

inline double f( double x )
{
    return(   S2 * sin( x/2 ) - L * x   );
}

double Bisection( double L,double R )
{
    double M;
    double fL = f(L) ,fR = f(R), fM;
    
    if( ABS( fR )<e )return R;
    if( ABS( fL )<e )return L;
    
    while( R-L>e )
    {
        M = ( L+R ) / 2;
        fM = f(M);
        if( ABS( fM )<e )
            return M;
        else if( fL*fM<0 )
            R = M, fR = fM;
        else
            L = M, fL = fM;
    }
    return L;
}

int main()
{
    cout.setf( ios::fixed );
    cout.precision( 3 );
    const double PI = acos( -1.000 );
    while( cin>>L>>n>>C,(  L>=0 || n>=0 || C>=0  ) )
    {
        if( C==0 || n==0 )
        {
            cout<<"0.000"<<endl;
            continue;
        }
        S = ( 1.000 + n*C ) * L;
        S2 = 2.000*S;
        theta = Bisection( e,PI-e );
        r = S/theta;
        cout<<(   r - r*cos( theta/2.000 )   )<<endl;
    }
}


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tryit1
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Posts: 119
Joined: Sun Aug 24, 2008 9:09 pm

Re: 10668 - Expanding Rods

Post by tryit1 » Thu Jan 01, 2009 2:33 am

i used long double , and EPS as 1e-13

Code: Select all

1000 100 0.0001
15000 10 0.00006
15000 20 0.00006
15000 20 0.00089
10 1 0.001
10 0 0.001
1 5 0.2333
5 1 0.2333
5300 100 0.5323
15 415 0.0044
15 15 3.333
-1 -1 -1

Code: Select all

61.329
225.020
318.255
1228.775
0.194
0.000
0.000
1.529
0.000
0.000
0.000

User avatar
plamplam
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Posts: 150
Joined: Fri May 06, 2011 11:37 am

Re: 10668 - Expanding Rods

Post by plamplam » Fri Jan 27, 2012 5:35 pm

I used binary search on theta, after getting a couple of wrong answers, when I handled cases like n = 0, l = 0 or c = 0, I got Accepted. Here are some cases:

Code: Select all

1000 100 0.0001
0 100 0.0001
1000 0 0.0001
1000 100 0
15000 10 0.00006
10 0 0.001
-112 -1121212 -1324

Code: Select all

61.329
0.000
0.000
0.000
225.020
0.000
You tried your best and you failed miserably. The lesson is 'never try'. -Homer Simpson

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