UVa 12301 An Angular Puzzle 平面角度计算

#include<iostream>
#include<cmath>
#include<cstdio>
#include<algorithm>
const double eps=1e-10;
const double PI=acos(-1);

using namespace std;

struct Point{
double x;
double y;
Point(double x=0,double y=0):x(x),y(y){}
void operator<<(Point &A) {cout<<A.x<<' '<<A.y<<endl;}
};

int dcmp(double x)  {return (x>eps)-(x<-eps); }

typedef  Point  Vector;

Vector  operator +(Vector A,Vector B) { return Vector(A.x+B.x,A.y+B.y);}

Vector  operator -(Vector A,Vector B) { return Vector(A.x-B.x,A.y-B.y); }

Vector  operator *(Vector A,double p) { return Vector(A.x*p,A.y*p);  }

Vector  operator /(Vector A,double p) {return Vector(A.x/p,A.y/p);}

// ps  cout

ostream &operator<<(ostream & out,Point & P) { out<<P.x<<' '<<P.y<<endl; return out;}

bool  operator< (const Point &A,const Point &B) { return A.x<B.x||(A.x==B.x&&A.y<B.y); }

bool  operator== ( const Point &A,const Point &B) { return dcmp(A.x-B.x)==0&&dcmp(A.y-B.y)==0;}

double  Dot(Vector A,Vector B) {return A.x*B.x+A.y*B.y;}

double  Cross(Vector A,Vector B)  {return A.x*B.y-B.x*A.y; }

double  Length(Vector A)  { return sqrt(Dot(A, A));}

double  Angle(Vector A,Vector B) {return acos(Dot(A,B)/Length(A)/Length(B));}

double  Area2(Point A,Point B,Point C ) {return Cross(B-A, C-A);}

Vector Rotate(Vector A,double rad) { return Vector(A.x*cos(rad)-A.y*sin(rad),A.x*sin(rad)+A.y*cos(rad));}
Vector Normal(Vector A) {double L=Length(A);return Vector(-A.y/L,A.x/L);}

Point GetLineIntersection(Point P,Vector v,Point Q,Vector w)
{
Vector u=P-Q;
double t=Cross(w, u)/Cross(v,w);
return P+v*t;

}

double DistanceToLine(Point P,Point A,Point B)
{
Vector v1=P-A; Vector v2=B-A;
return fabs(Cross(v1,v2))/Length(v2);

}

double DistanceToSegment(Point P,Point A,Point B)
{
if(A==B)  return Length(P-A);

Vector v1=B-A;
Vector v2=P-A;
Vector v3=P-B;

if(dcmp(Dot(v1,v2))==-1)    return  Length(v2);
else if(Dot(v1,v3)>0)    return Length(v3);

else return DistanceToLine(P, A, B);

}

Point GetLineProjection(Point P,Point A,Point B)
{
Vector v=B-A;
Vector v1=P-A;
double t=Dot(v,v1)/Dot(v,v);

return  A+v*t;
}

bool  SegmentProperIntersection(Point a1,Point a2,Point b1,Point b2)
{
double c1=Cross(b1-a1, a2-a1);
double c2=Cross(b2-a1, a2-a1);
double c3=Cross(a1-b1, b2-b1);
double c4=Cross(a2-b1, b2-b1);

//cout<<c1<<c2<<c3<<c4<<endl;
return dcmp(c1)*dcmp(c2)<0&&dcmp(c3)*dcmp(c4)<0 ;

}

bool  OnSegment(Point P,Point A,Point B)
{
return dcmp(Cross(P-A, P-B))==0&&dcmp(Dot(P-A,P-B))<0;
}

double PolygonArea(Point *p,int n)
{
double area=0;

for(int i=1;i<n-1;i++)
{
area+=Cross(p[i]-p[0], p[i+1]-p[0]);

}
return area/2;

}

Point  read_point()
{
Point P;
scanf("%lf%lf",&P.x,&P.y);
return  P;
}

int main()
{
double a,b,c,d,e;
while(cin>>a>>b>>c>>d>>e)
{
if(a==0)  break;
if(dcmp(a+b+c+d+e-180)!=0)  cout<<"Impossible"<<endl;

else
{
a=a/180*PI;
b=b/180*PI;
c=c/180*PI;
d=d/180*PI;
e=e/180*PI;

Point A=Point(0,0);
Point B=Point(1,0);

Vector AC=Vector(1,tan(b+c));
Vector BC=Vector(1,-tan(d+e));

// Point C=GetLineIntersection(A, AC, B, BC);

Vector AE=Vector(1,tan(c));
Vector BD=Vector(1,-tan(e));

Point E=GetLineIntersection(A, AE, B, BC);

Point D=GetLineIntersection(A, AC, B, BD);

double AED=Angle(D-E, A-E);

printf("%.2lf\n",AED/PI*180);

}

}
}