OJ-Problems-Source/HDOJ/2241_autoAC.cpp
2016-08-22 00:09:53 +08:00

54 lines
1.1 KiB
C++

#include <iostream>
#include <math.h>
using namespace std;
#define N 10005
#define EPS 1e-10
double MIN;
double n;
double x[N],y[N];
double yyy(double xx,int id)
{
double yy,k;
k=(y[id+1]-y[id])/(x[id+1]-x[id]);
yy=y[id]+k*(xx-x[id]);
return yy;
}
void san_fen(int m)
{
int i;
double x1,y1,x2,y2,midx1,midx2,d,elem1,elem2;
for(i=0;i<m-1;i++)
{
x1=x[i];y1=y[i];
x2=x[i+1];y2=y[i+1];
d=(y2-y1)/(x2-x1);
do
{
midx1=(x1+x2)/2;
midx2=(midx1+x2)/2;
elem1=n/(midx1*midx1)+yyy(midx1,i);
elem2=n/(midx2*midx2)+yyy(midx2,i);
if(elem1>elem2)
x1=midx1;
else if(elem1<elem2)
x2=midx2;
}
while(fabs(elem1-elem2)>EPS);
if(MIN>elem1)
MIN=elem1;
}
}
int main()
{
int m,i;
while(scanf("%d%lf",&m,&n)!=EOF)
{
MIN=999999.0;
for(i=0;i<m;i++)
scanf("%lf%lf",&x[i],&y[i]);
san_fen(m);
printf("%.3lf\n",MIN);
}
return 0;
}