hdu 4736 This Is The Job The Bear Finds(2013年成都ACM网络赛)
// Time 1718 ms; Memory 1500 K
#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#define eps 1e-10
#define sqr(a) ((a)*(a))
#define pi (2.0*asin(1.0))
using namespace std;
double ma[100010];
int sig(double a)
{
return (a>eps)-(a<-eps);
}
typedef struct point
{
double x,y;
point(double xx=0,double yy=0):x(xx),y(yy){}
}vector;
struct node
{
double ang,d;
point c;
}th[10010];
point pt[10010];
bool operator < (point a,point b)
{
return a.x<b.x || (a.x==b.x && a.y<b.y);
}
vector operator - (point a,point b)
{
return vector(a.x-b.x,a.y-b.y);
}
point operator + (point a,vector b)
{
return point(a.x+b.x,a.y+b.y);
}
vector operator * (vector a,double b)
{
return vector(a.x*b,a.y*b);
}
vector operator / (vector a,double b)
{
return vector(a.x/b,a.y/b);
}
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-a.y*b.x;
}
double len(vector a)
{
return sqrt(sqr(a.x)+sqr(a.y));
}
double angle(vector a,vector b)
{
double d=dot(a,b)/len(a)/len(b);
if(sig(d-1)==0) return 0;
if(sig(d+1)==0) return pi;
return acos(d);
}
double dis(point a,point b,point p)
{
return fabs(cross(b-a,p-a))/len(b-a);
}
vector rot(vector a,double b)
{
double s=sin(b),c=cos(b);
return vector(a.x*c-a.y*s,a.x*s+a.y*c);
}
vector rsize(vector a,double b)
{
b/=len(a);
return vector(a.x*b,a.y*b);
}
point bcenter(int n,double &l)
{
point p,s;
double tp,area=0,tpx=0,tpy=0;
point t1=pt[0],t2=pt[0];
p=pt[0];
l=0;
for(int i=1;i<=n;i++)
{
s.x=pt[i==n ? 0 : i].x;
s.y=pt[i==n ? 0 : i].y;
if(s<t1) t1=s;
else if(t2<s) t2=s;
l+=len(pt[i-1]-s);
tp=cross(p,s);area+=tp/2;
tpx+=(p.x+s.x)*tp;tpy+=(p.y+s.y)*tp;
p.x=s.x;p.y=s.y;
}
if(sig(area)==0) s=(t1+t2)/2;
else
{
s.x=tpx/(6*area);s.y=tpy/(6*area);
}
return s;
}
point getp(point p,vector v,point cp,double r)
{
double a=v.x,b=p.x-cp.x,c=v.y,d=p.y-cp.y;
double e=sqr(a)+sqr(c),f=2*(a*b+c*d),g=sqr(b)+sqr(d)-sqr(r);
double del=sqr(f)-4*e*g;
double t=(-f+sqrt(del))/(2*e);
return p+v*t;
}
int main()
{
int i,j,k,u,t,n,m,cnt,my,cas=1;
double l,sl,rad,lp,lq,ang1,ang2,ds,ll;
point ct,ct1,ct2,g;
vector v,w;
scanf("%d",&t);
while(t--)
{
scanf("%d",&n);
my=0;
for(i=0;i<n;i++)
{
scanf("%lf%lf",&pt[i].x,&pt[i].y);
if(sig(pt[my].x-pt[i].x)>0) my=i;
}
scanf("%lf%lf%d",&ct.x,&ct.y,&m);
while(sig(cross(pt[my]-ct,pt[(my-1+n)%n]-pt[my]))>0) my=(my-1+n)%n;
g=bcenter(n,sl);
v=ct-g;
ll=len(v);
ct1=ct;
th[0].c=ct;
for(j=my,k=0;k<n;k++)
{
u=(j+k)%n;
lp=len(pt[u]-ct1);
ct2=getp(pt[u],pt[(u+1)%n]-pt[u],g,ll);
th[k+1].ang=th[k].ang+angle(ct1-g,ct2-g);
th[k+1].d=th[k].d+len(pt[u]-ct2)-lp;
th[k+1].c=ct2;
ct1=ct2;
}
for(i=0;i<m;i++)
{
scanf("%lf",&l);
cnt=(int)l/sl;
l=l-cnt*sl;
rad=cnt*2*pi;
int right=n,left=1,mid=(n+1)/2;
double tmp1,tmp2;
while(left<=right)
{
tmp1=l-th[mid].d;
tmp2=l-th[mid-1].d;
if(sig(tmp1)==0)
{
mid++;break;
}
if(sig(tmp2)==0) break;
if(sig(tmp1)<0 && sig(tmp2)>0)
break;
if(sig(tmp1)>0) left=mid+1;
else right=mid-1;
mid=(left+right)/2;
}
j=mid;
if(left>right) j++;
rad+=th[j-1].ang;
l-=th[j-1].d;
if(sig(l)>0)
{
u=(my+j-1)%n;
lp=len(pt[u]-g);
lq=len(th[j-1].c-pt[u])+l;
ang1=acos((sqr(lp)+sqr(ll)-sqr(lq))/(2*lp*ll));
ang2=ang1-angle(pt[u]-g,th[j-1].c-g);
rad+=ang2;
}
ma[i]=rad/pi*180;
}
printf("Case #%d:\n",cas++);
for(i=0;i<m;i++)
printf("%.3lf\n",ma[i]);
}
return 0;
}