68 lines
1.1 KiB
C++
68 lines
1.1 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <cmath>
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#include <algorithm>
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#define INF 1E9
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using namespace std;
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double X[301],Y[301];
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int n,ans;
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double x,y;
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inline double c(int i)
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{
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return (X[i]-x)*(X[i]-x)+(Y[i]-y)*(Y[i]-y);
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}
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int calc()
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{
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int i,ans=0;
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for(i=0;i<n;i++)
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{
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if(c(i)>1.0+1e-8)continue;
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ans++;
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}
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return ans;
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}
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void center(int i,int j)
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{
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double x1=X[i]-X[j],y1=Y[i]-Y[j],len,k;
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double a,b;
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if(x1==0)
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a=1,b=0;
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else if (y1==0)
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a=0,b=1;
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else
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{
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k=-1/y1*x1;
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len=sqrt(1+k*k);
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a=1.0/len;
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b=k/len;
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}
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len=1-(x1*x1+y1*y1)/4;
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if(len<0)return;
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len=sqrt(len);
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x1=(X[i]+X[j])/2.0;y1=(Y[i]+Y[j])/2.0;
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a*=len;b*=len;
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x=x1+a;y=y1+b;
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ans=max(ans,calc());
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x=x1-a;y=y1-b;
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ans=max(ans,calc());
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}
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int main()
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{
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int T;
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int i,j;
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scanf("%d",&T);
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while(T--)
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{
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scanf("%d",&n);
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for(i=0;i<n;i++)
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scanf("%lf%lf",&X[i],&Y[i]);
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ans=0;
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for(i=0;i<n;i++)
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for(j=i;j<n;j++)
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center(i,j);
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printf("%d\n",ans);
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}
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}
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