10310 - Dog and Gopher

[bugzpodder]

anything wrong with these?

Input

Code: Select all

0 0 0 0 0

11 0 0 0 0
0.001 0
0 0.001
-0.001 0
0 -0.001
5 4
-10000 -10000
0 0
0 0
0 0
0 0
0 0

3 3 4 -10 0
-10000 -10000
0 0
3 4

3 3 4 -9.999 0
-10000 -10000
0 0
-390 -390

1 1.000 1.000 2.000 2.000
1.500 1.500
 
2 2.000 2.000 1.000 1.000
1.500 1.500
2.500 2.500

OUtput

Code: Select all

The gopher cannot escape.
The gopher can escape through the hole at (0.000,0.000).
The gopher can escape through the hole at (0.000,0.000).
The gopher cannot escape.
The gopher cannot escape.
The gopher can escape through the hole at (2.500,2.500).

[junjieliang]

Hi,

My output is almost the same as yours, but I have a space between the numbers (after the comma). Could that be your problem?

Code: Select all

My output
The gopher cannot escape.
The gopher can escape through the hole at (0.000, 0.000).
The gopher can escape through the hole at (0.000, 0.000).
The gopher cannot escape.
The gopher cannot escape.
The gopher can escape through the hole at (2.500, 2.500).

[Sujoy Kumar Chowdhury]

There should not be any space after the comma

[bugzpodder]

Thanks to Vassili I have fixed a precision error while reading the data.

[nibbler]

The following codes both get WA:

Code: Select all

#include <stdio.h>

long long dist(long long a,long long b,long long x,long long y) {
	return (a-x)*(a-x)+(b-y)*(b-y);
}

int main()
{
	double 		ddx,ddy,dgx,dgy,dx,dy;
	long long	ldx,ldy,lgx,lgy,lx,ly;
	int N;
	while (scanf ("%d %lf %lf %lf %lf",&N,&ddx,&ddy,&dgx,&dgy)==5) {
		int escape=0;
		ldx=(long long)(ddx*1000ULL);
		ldy=(long long)(ddy*1000ULL);
		lgx=(long long)(dgx*1000ULL);
		lgy=(long long)(dgy*1000ULL);
		for (int i=0;i<N;i++) {
			scanf ("%lf %lf",&dx,&dy);
			lx=(long long)(dx*1000ULL);
			ly=(long long)(dy*1000ULL);
			if (escape==0) {
				if ( (4ULL*dist(ldx,ldy,lx,ly)) <= (dist(lgx,lgy,lx,ly)) ) {
					printf ("The gopher can escape through the hole at (%.3lf,%.3lf).\n",dx,dy);
					escape=1;
				}
			}
		}
		if (escape==0) printf ("The gopher cannot escape.\n");
	}
	return 0;
}

Code: Select all

#include <stdio.h>

double dist(double a,double b,double x,double y) {
	return (a-x)*(a-x)+(b-y)*(b-y);
}

int main()
{
	double dx1,dy1,dx2,dy2;
	double dtx,dty;
	int N,esc=0;
	while (scanf ("%d %lf %lf %lf %lf",&N,&dx1,&dy1,&dx2,&dy2)==5) {
		esc=0;
		for (int i=0;i<N;i++) {
			scanf ("%lf %lf",&dtx,&dty);
			if (esc==0) {
				if (4.0*dist(dx1,dy1,dtx,dty)<=dist(dx2,dy2,dtx,dty)) {
					printf ("The gopher can escape through the hole at (%.3lf,%.3lf)\n",dtx,dty);
					esc=1;
				}
			}
		}	
		if (esc==0) printf ("The gopher cannot escape.\n");
	}
	return 0;
}

I just don't know where is the problem.

[sohel]

I don't know about the first one, but your second code does not give the correct output for the sample....

Sample output
[c]
The gopher cannot escape.
The gopher can escape through the hole at (2.500,2.500).
[/c]

Your output
[c]
The gopher cannot escape.
The gopher can escape through the hole at (2.500,2.500)
[/c]

Can you see the difference...

















.... "oh! yes I should add a period at the end of the second line."

[J&Jewel]

is this is a valid in c or c++
all are in double
r1=sqrt(pow(x1-h1,2.0)+pow(y1-o1,2.0));

[J&Jewel]

can this ? correct for this problem..?
r1=sqrt(pow((x1-h1),2.0)+pow((y1-o1),2.0));
all in double.

[PerHagen]

my code is but is wrong !!

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

void main (void){
double dg,dp,hx,hy,gx,gy,px,py,rhx,rhy;
int i,nhole;
while (scanf("%d %lf %lf %lf %lf",&nhole,&gx,&gy,&px,&py)==5){
int k=0;

for (i=1;i<=nhole;i++){
scanf("%lf %lf",&hx,&hy) ;
dg=sqrt( (hx-gx)*(hx-gx) + (hy-gy)*(hy-gy) );
dp=sqrt( (hx-px)*(hx-px) + (hy-py)*(hy-py) );
if(k==0){
if (2*dg<dp){
k=1;
rhx=hx;rhy=hy;
}
}

}
if (k==0) printf("The gopher cannot escape.\n\n");
else printf("The gopher can escape through the hole at (%.3lf,%.3lf).\n\n"
,rhx,rhy);
}


}

help me

[PerHagen]

any answer please !!!

any I/O please


bytes!

[Raj Ariyan]

The main problems with this type of problem is precission error. You used double,in my accepted code i used long double. But there are some other reason which led you wrong answer. Those are ....

1. Why u print two new lines every times ?


You write..

if (k==0) printf("The gopher cannot escape.\n\n");
else printf("The gopher can escape through the hole at (%.3lf,%.3lf).\n\n"
,rhx,rhy);

u should print only one new line.

2. Again you write ...

if (2*dg<dp)

but it can be equal. So use...
if(2*dg==dp || 2*dg<dp)

May it helps you. Good luck.

[sumankar]

Floating point comparisons should be done with a little care in the form of some tolerance e.g. 1e-4,1e-6 ...etc.Read past threads for more info.

Regards,
Suman.

[PerHagen]

thx

I got AC !!!

sorry ... but you have I/O of 507(jill again rides )

bytes!

[sumankar]

i/o?Sorry?

Quote sufficient material / write a tad bit more just to let us know who your intended audience is.

Regards,
Suman.

[shadow]

The problem hasnt precisely defined the answer when the dog and the gopher both reach a hole at the same time. I think the answer in this case is "can reach".