http://acm.hdu.edu.cn/showproblem.php?pid=5120
圓環的交 = 大圓交-2個大小圓交+小圓交
最討厭這些模板題!幹.
<span style="font-size:14px;">#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <string>
#include <queue>
#include <map>
#include <iostream>
#include <sstream>
#include <algorithm>
using namespace std;
#define RD(x) scanf("%d",&x)
#define RD2(x,y) scanf("%d%d",&x,&y)
#define RD3(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define clr0(x) memset(x,0,sizeof(x))
#define clr1(x) memset(x,-1,sizeof(x))
#define eps 1e-9
const double pi = acos(-1.0);
typedef long long LL;
const int inf = 1000000000;
const int maxn = 1e6+5;
const double Pi=acos(-1.0);
double Rad2Deg(double rad){
return (rad*180.0/Pi);
}
double Deg2Rad(double deg){
return (deg*Pi/180.0);
}
double ArcCos(double val){
return Rad2Deg(acos(val));
}
double Sin(double deg){
return sin(Deg2Rad(deg));
}
struct CIRCLE{
double x;
double y;
double r;
CIRCLE(){}
CIRCLE(double xx,double yy,double rr){
x=xx; y=yy; r=rr;
}
};
struct POINT{
double x;
double y;
POINT():x(0),y(0){};
POINT(double xx,double yy):x(xx),y(yy){ }
};
double Distance(const POINT& a,const POINT& b){
return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
POINT Center(const CIRCLE& circle){
return POINT(circle.x,circle.y);
}
double Area(const CIRCLE& circle){
return Pi*circle.r*circle.r;
}
double CommonArea(const CIRCLE& A,const CIRCLE &B){
double area=0.0;
const CIRCLE& M=(A.r>B.r)?A:B;
const CIRCLE& N=(A.r>B.r)?B:A;
double D=Distance(Center(M),Center(N));
if((D<M.r+N.r)&&(D>M.r-N.r)){
double cosM=(M.r*M.r+D*D-N.r*N.r)/(2.0*M.r*D);
double cosN=(N.r*N.r+D*D-M.r*M.r)/(2.0*N.r*D);
double alpha=2.0*ArcCos(cosM);
double beta=2.0*ArcCos(cosN);
double TM=0.5*M.r*M.r*Sin(alpha);
double TN=0.5*N.r*N.r*Sin(beta);
double FM=(alpha/360.0)*Area(M);
double FN=(beta/360.0)*Area(N);
area=FM+FN-TM-TN;
}else if(D<=M.r-N.r){
area=Area(N);
}
return area;
}
double work()
{
double r,R;
double x1,y1;
double x2,y2;
//cin>>r>>R>>x1>>y1>>x2>>y2;
scanf("%lf%lf%lf%lf%lf%lf",&r,&R,&x1,&y1,&x2,&y2);
CIRCLE cr1(x1,y1,r);
CIRCLE cr2(x2,y2,r);
CIRCLE cR1(x1,y1,R);
CIRCLE cR2(x2,y2,R);
double ans=CommonArea(cR1,cR2)+CommonArea(cr1,cr2);
ans-=CommonArea(cr1,cR2);
ans-=CommonArea(cR1,cr2);
return ans;
}
int main()
{
int _,cas = 1;
RD(_);
while(_--){
printf("Case #%d: %.6lf\n",cas++,work());
}
return 0;
}
/*
*/
</span>