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