mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
64 lines
1.8 KiB
C++
64 lines
1.8 KiB
C++
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#include<stdio.h>
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#include<math.h>
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#define eps 1e-5
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#define PI 3.1415926535897932384626
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int n,a[10001];
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double angle;
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int i,j,k,maxtop;
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double dis[10001],t,top,ans,low,h;
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int main()
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{
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while(~scanf("%d%lf",&n,&angle))
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{
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if(angle<-eps) for(i=n-1;i>=0;i--) scanf("%d",&a[i]);
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else for(i=0;i<n;i++) scanf("%d",&a[i]);
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if(angle<-eps) angle=-angle;
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angle=PI*angle/180.0;
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t=-1;ans=0;
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for(i=0;i<n;i++)
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{
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dis[i]=((i+1)*tan(angle)+a[i]*1.0)/sqrt(tan(angle)*tan(angle)+1);
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if(t<dis[i]){t=dis[i];maxtop=i;}
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}
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for(i=0;i<maxtop;i++)
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{
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top=a[i];
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for(j=i+1;j<=maxtop;j++)
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{
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if(dis[j]>dis[i]+eps)
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{
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if(dis[j]-sin(angle)>dis[i]+eps)
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{
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top-=(j-i-1)*1.0*tan(angle);
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ans+=(j-i-1)*(j-i-1)*0.5*tan(angle);
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}
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else
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{
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top-=(a[i]-a[j])*1.0;
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ans+=(a[i]-a[j])*(a[i]-a[j])*0.5/tan(angle);
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}
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for(k=i+1;k<j;k++)
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ans+=(top-a[k])*1.0;
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i=j-1;
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break;
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}
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}
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}
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for(i=n-1;i>maxtop;i--)
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{
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for(j=i-1;j>=maxtop;j--)
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{
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h=i-j;
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low=h*tan(angle)-(a[j+1]-a[i]);
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top=(h-1)*tan(angle)-(a[j+1]-a[i]);
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ans+=(top+low)/2.0;
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if(dis[j]>dis[i]+eps)
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break;
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}
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i=j+1;
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}
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printf("%.2lf\n",ans);
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}
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return 0;
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}
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