54 lines
1.2 KiB
C++
54 lines
1.2 KiB
C++
#include<iostream>
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#include<cstdio>
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#include<cstring>
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#include<cstdlib>
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#include<cmath>
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#include<algorithm>
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#define inf 0x7fffffff
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#define exp 1e-10
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#define PI 3.141592654
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using namespace std;
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typedef long long ll;
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struct Point
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{
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double x,y;
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Point (double x=0,double y=0):x(x),y(y){}
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};
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double dist(Point a,Point b)
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{
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double x=(a.x-b.x)*(a.x-b.x);
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double y=(a.y-b.y)*(a.y-b.y);
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return sqrt(x+y);
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}
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double Area_of_overlap(Point c1,double r1,Point c2,double r2)
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{
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double d=dist(c1,c2);
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if (r1+r2<d+exp) return 0;
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if (d<fabs(r1-r2)+exp)
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{
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double r=min(r1,r2);
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return PI*r*r;
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}
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double x=(d*d+r1*r1-r2*r2)/(2*d);
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double t1=acos(x/r1);
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double t2=acos((d-x)/r2);
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return r1*r1*t1+r2*r2*t2-d*r1*sin(t1);
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}
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int main()
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{
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int t,ncase=1;
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double r,R;
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Point a,b;
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scanf("%d",&t);
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while (t--)
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{
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scanf("%lf%lf",&r,&R);
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scanf("%lf%lf%lf%lf",&a.x,&a.y,&b.x,&b.y);
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double bb_area=Area_of_overlap(a,R,b,R);
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double bs_area=Area_of_overlap(a,R,b,r);
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double ss_area=Area_of_overlap(a,r,b,r);
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printf("Case #%d: %.6lf\n",ncase++,bb_area-2.0*bs_area+ss_area);
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}
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return 0;
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}
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