10215 - The Largest/Smallest Box ...

[little joey]

Did you look at the problemstats of this problem? It's impossible to get Accepted using Pascal. I wrote two identical programs, one in Pascal (my 'natural' language) and one in C, after many hours of frustration. The C program got accepted at once.

I guess it's all about implementation specific rounding errors and a lazy problemsetter... (Mark my words: I don't say lousy, but lazy. I consider Manzoor to be one of the most original and productive problemsetters, but IMHO he makes some slips in the rounding error department once in a while, see 10402 for which nobody to date reproduced his (seemingly) erronious result (124 WA and 0 AC point in that direction)).

My Pascal code is (WA):[pascal]program p10215;

var
w,l,x,x1,x2,vol1,vol2:real;
begin
while not eof do begin
readln(w,l);
if (w>l) then begin
x:=w;
w:=l;
l:=x;
end;
x1:=((l+w)-sqrt(l*l+w*w-l*w))/6.0;
x2:=((l+w)+sqrt(l*l+w*w-l*w))/6.0;
vol1:=x1*(w-2.0*x1)*(l-2.0*x1);
vol2:=x2*(w-2.0*x2)*(l-2.0*x2);
if (vol2<vol1) then x:=x1 else x:=x2;
writeln(x:0:3,' 0.000 ',(w/2.0):0:3);
end;
end.[/pascal]
And my C code is (AC):[c]#include <stdio.h>
#include <math.h>

int main(void){
double w,l,x,x1,x2,vol1,vol2;

while (scanf("%lf %lf",&w,&l)==2) {
if (w>l) {
x=w;
w=l;
l=x;
}
x1=((l+w)-sqrt(l*l+w*w-l*w))/6.0;
x2=((l+w)+sqrt(l*l+w*w-l*w))/6.0;
vol1=x1*(w-2.0*x1)*(l-2.0*x1);
vol2=x2*(w-2.0*x2)*(l-2.0*x2);
if (vol2<vol1) x=x1; else x=x2;
printf("%.3lf %.3lf %.3lf\n",x,0.0,w/2.0);
}
return 0;
}[/c]
Looks the same, feels the same, tastes the same. Please don't steal it...

[Derk]

I switched float to double and got AC.

[Eric]

Oh, Joey you are right.
There is NONE accepted with Pascal.
Thank you. I think I need to switch to the next problem.

[yiuyuho]

The problem says:

Given the width and height of the box, you will have to find the value of x for which the box has maximum and minimum volume.


Input

The input file contains several lines of input. Each line contains two positive floating-point numbers L(0<L<10000) and W(0<W<10000); which indicate the length and width of the card respectively.

so are we getting the length and width of the card (as in input specification) or the width and height of the box???

[midra]

Here is my code:

[c]
#include <stdio.h>

int main()
{
double l,w;
double res1,res2,a,b,c;
while(scanf("%lf %lf",&l,&w)!=EOF)
{
a=12;
b=4*(w+l);
c=w*l;
res1=(b + sqrt(b*b - 4*a*c))/(2*a);
res2=(b - sqrt(b*b - 4*a*c))/(2*a);
if (res1>res2)
printf("%.3lf 0.000 %.3lf\n",res2,res1);
else
printf("%.3lf 0.000 %.3lf\n",res1,res2);
}
return 0;
}
[/c]

It seems to be ok....
plz if someone knows help me!!

[marian]

I switched long double to double and got AC

[shamim]

I think this problem should have a correction program for it.

[minskcity]

Can anybody see what's wrong with this code?[cpp]#include <iostream>
using namespace std;

long double a, b;

inline long double f(const long double &x){
return (a - 2*x)*(b - 2*x)*x;
}

int main(){

while(cin >> a >> b){
long double mn = 0;
long double mx = a > b ? b/2 : a/2;

while(mx - mn > 0.0000000001)
if(f(mn + (mx - mn)/3.0) > f(mn + 2.0*(mx - mn)/3.0)) mx = mn + 2.0*(mx - mn)/3.0;
else mn = mn + (mx - mn)/3.0;
cout.setf(ios::fixed);
cout.precision(3);
cout << mn << " " << 0.0 << " " << (a > b ? b/2 : a/2) << endl;

}

return 0;
}
[/cpp]

[Abednego]

minskcity, you are using long double. marian said his code got AC when he switched from long double to double. This is my code, and it works:

Code: Select all

int main()
{
    double L, W;
    while( cin >> L >> W )
        printf( "%.3f %.3f %.3f\n",
            ( L + W - sqrt( ( double )( L*L - L*W + W*W ) ) ) / 6.0,
            0.0, ( W <? L ) * 0.5 );
    return 0;
}

[randomtaiwanese]

someone wanna check my code???
btw... formatting decimals in java is a pain in the ass
[java]import java.io.IOException;
import java.util.StringTokenizer;
import java.text.NumberFormat;

class Main
{
static String ReadLn(int maxLg)
{
byte lin[]=new byte[maxLg];
int lg=0,car=-1;
try
{
while(lg<maxLg)
{
car=System.in.read();
if ((car<0)||(car=='\n'))
break;
lin[lg++]+=car;
}
}
catch(IOException e)
{
return(null);
}
if ((car<0)&&(lg==0))
return(null);
return (new String (lin, 0, lg));
}
public static void main(String[] args)
{
Main newMain = new Main();
newMain.start();
}
void start()
{
String input;
StringTokenizer tokenizer;
double w,l,m;
while ((input=Main.ReadLn(20))!=null)
{
tokenizer = new StringTokenizer(input);
l = new Double(tokenizer.nextToken()).doubleValue();
w = new Double(tokenizer.nextToken()).doubleValue();
m = Math.min(l,w);
System.out.print(FormatDecimal((((w+l)-Math.sqrt((w*w+l*l-w*l)))/6.0),3)+" 0.000 ");
System.out.println(FormatDecimal(m/2,3));
}
}
String FormatDecimal(double inp,int dec)
{
String in = new String(new Double(inp).toString());
NumberFormat nf = NumberFormat.getInstance();
nf.setGroupingUsed(false);
nf.setMaximumFractionDigits(dec);
in = nf.format(new Double(in).doubleValue());
int k=0;
if(in.charAt(0)=='.')
in = "0"+in;
while((in.charAt(k)!='.')&&!(k>=in.length()-1))
{
if(k<in.length())
{
if(in.charAt(k)=='.')
break;
else k++;
}
else break;
}
int diff = in.length()-k-1;
if(in.charAt(k)!='.')
{
in+=".";
for(int i=0;i<dec;i++) in+="0";
}
else if(dec>diff)
for(int i=0;i<(dec-diff);i++)
in+="0";
return in;
}
}[/java]

[little joey]

Did you read my previous posting? It's impossible to get accepted in Pascal, and my strong impression is that it's also impossible to get accepted in Java. To date there are 599 people that got accepted, non of them with Java or Pascal.
Rewrite your code in C or C++.

[Abednego]

Holy mother of god!
I think your only mistake is choosing the wrong language for this problem. :-)

Somebody correct me if I'm wrong, but Java's NumberFormat by default rounds 0.5 to the nearest even number (which is 0), and printf() rounds up (which is 1). Since changing double to long double gives Wrong Answer, this little detail could be what is wrong with your code.

[randomtaiwanese]

Did you read my previous posting? It's impossible to get accepted in Pascal, and my strong impression is that it's also impossible to get accepted in Java. To date there are 599 people that got accepted, non of them with Java or Pascal.
Rewrite your code in C or C++.

shame, becuase i have spent soo much time on writing a method on formatting a double value to a certain decimal place... ><

[randomtaiwanese]

Holy mother of god!
I think your only mistake is choosing the wrong language for this problem.

Somebody correct me if I'm wrong, but Java's NumberFormat by default rounds 0.5 to the nearest even number (which is 0), and printf() rounds up (which is 1). Since changing double to long double gives Wrong Answer, this little detail could be what is wrong with your code.

nah... java isnt this bad, it is only just about 3-5 times slower than other languages if both uses the best compiler, but because of the STONEAGE java compiler they have... java is like 10 times slower, a program with just ONE println() method takes 0.004 seconds to run on the OJ

[Darko]

Sigh...

I couldn't find what was wrong with my code (Java), so I came here, read that thing, went and checked the stats - 791 so far, C/C++ only.

That would explain some other WAs on similarly easy problems, I think (10137 (AC at PC), 10056...)

I guess I'll just skip any problems involving precision. Yes, I know I could just submit it in C and be done with it, but that's not the point.

Darko

P.S. Btw, people got AC by printing 3 0's? (I tried both 2 and 3) From the problem description one could say that if x_min = 0, you print only one, not two?