计算几何-UVa10652

db Area(D*R,int n){
    db S=0.0;
    for(int i=1;i<n;i++)S+=Cross(R[i]-R[1],R[i+1]-R[1]);
    return S/2;
}

int n,cnt=0;db S1=0.0;
for(scanf("%d",&n);n--;){        
  db x,y,w,h,j,a;
  scanf("%lf%lf%lf%lf%lf",&x,&y,&w,&h,&j);
  D O(x,y);a=-Rad(j);
  R[++cnt]=O+Rotate(V(-w/2,-h/2),a);
  R[++cnt]=O+Rotate(V( w/2,-h/2),a);
  R[++cnt]=O+Rotate(V(-w/2, h/2),a);
  R[++cnt]=O+Rotate(V( w/2, h/2),a);
  S1+=w*h;
}
int m=Andrew(R,cnt,A);
db S2=Area(A,m);
printf("%.1lf%%\n",S1*100.0/S2);