I have two ACCEPTED solution that gives different results (difference greater than 1E-5) in approximately 7.5-8% points.
Is this normal? :)

If you have access:
"Correct" solution: http://acm.timus.ru/getsubmit.aspx/6557034.cpp
Wrong solution: http://acm.timus.ru/getsubmit.aspx/6554840.cpp

Here some of this points:

-5.4 -4.0
-0.0 -4.0
5.4 -4.0
-5.4 -2.8
-2.7 -2.8
-2.4 -2.8
-2.1 -2.8
-0.6 -2.8
0.6 -2.8
2.1 -2.8
2.4 -2.8
2.7 -2.8
5.4 -2.8
-2.7 -2.5
-0.6 -2.5
0.6 -2.5
2.7 -2.5
-2.7 -2.2
2.7 -2.2
-5.1 -1.9
-4.8 -1.9
-1.8 -1.9
-0.3 -1.9
0.3 -1.9
1.8 -1.9
4.8 -1.9
5.1 -1.9
-4.2 -0.7
-2.7 -0.7
2.7 -0.7
4.2 -0.7
-1.8 -0.4
1.8 -0.4
-1.8 -0.1
1.8 -0.1
-1.8 0.2
1.8 0.2
-4.2 0.5
-2.1 0.5
-1.8 0.5
1.8 0.5
2.1 0.5
4.2 0.5
-4.2 0.8
4.2 0.8
-4.2 1.7
4.2 1.7
-5.1 2.0
5.1 2.0
-2.7 2.3
2.7 2.3
-5.4 2.6
-2.7 2.6
-2.4 2.6
-0.6 2.6
0.6 2.6
2.4 2.6
2.7 2.6
5.4 2.6
-5.4 2.9
-2.7 2.9
-2.4 2.9
-2.1 2.9
-0.6 2.9
0.6 2.9
2.1 2.9
2.4 2.9
2.7 2.9
5.4 2.9

Admins, please add these tests:
0.683013 0.2
0.683013 0.3
0.583013 0.4
0.583013 0.5

Just add them :)

Explain please someone sample, coz I don't understand how can we get answer 0. My answer is 0.3660.

here my code
#include<stdio.h>
#include<math.h>
#define R  1.3660254037844
#define R2 2.7320508075689
#define PI 3.1415926535898
#define H  2.3660254037844

double xShift[] = {R2, R, -R, -R2, -R, R };
double yShift[] = {0, H, H, 0, -H, -H};

double dist(double x1, double y1, double x2, double y2){
    x2 -= x1 ;
    y2 -= y1 ;
    return sqrt(x2*x2 + y2*y2);
}
double calc(double xUse, double yUse){
    int i,j,k;
    double x, y, L, RadiusI, alpha;
    double mL = 1000;//dist( 0, 0, xUse+R, yUse);
    for (k = 0; k<6;k++){
            L = dist(xUse, yUse, xShift[k]/2.0, yShift[k]/2.0);
            mL = (mL<L)?mL:L;
    }

    for (i = 1; i<10;i++){
        RadiusI = R2*i;
        alpha = PI/3.0/i;
        for (j = 0; j<6*i;j++){
            x = RadiusI * cos(alpha * j ) ;
            y = RadiusI * sin(alpha * j ) ;

            for (k = 0;k<6;k++){
                L = dist(xUse, yUse, xShift[k]/2.0 + x, yShift[k]/2.0+y);
                mL = (mL<L)?mL:L;
            }
        }
    }
    return mL;
}
int main(){

    double xCenter , yCenter;
    scanf("%lf",&xCenter);
    scanf("%lf",&yCenter);

    xCenter = fabs(xCenter);
    yCenter = fabs(yCenter);

    double L1 = calc(xCenter - R, yCenter);
    double L2 = calc(yCenter - R, xCenter);
    double minL = (L1 < L2)?L1:L2;
    minL = fabs(minL);


    printf("%.4lf",minL);

    return 0;
}

Shouldn't the answer to the sample be 0.3660?
I've solved this problem assuming, that pyramid lies on triangular edge. It seems to me that it is wrong suggestion, nevertheless it got AC. It seems to me, that pyramid should be firstly rotated to lay on one of the triangular face - then the answer is 0.3660. Am I wrong?

Edited by author 09.11.2009 02:17

Is 70 turns enough to reach all points which are at the distance of 25 from the initial point?

I have no idea .My email tiger88@mail.ru