hdu 4667 Building Fence < 计算几何模板>

 //大白p263
 #include <cmath>
 #include <cstdio>
 #include <cstring>
 #include <string>
 #include <queue>
 #include <functional>
 #include <set>
 #include <iostream>
 #include <vector>
 #include <algorithm>
 using namespace std;
 const double eps=1e-;//精度
 const int INF=0x3f3f3f3f;
 const double PI=acos(-1.0);
 inline int dcmp(const double& x){//判断double等于0或。。。
     if(fabs(x)<eps)return ;else return x<?-:;
 }
 struct Point{
     double x,y;
     Point(){}
     Point(double x,double y):x(x),y(y){}
 };
 typedef Point Vector;
 typedef vector<Point> Polygon;
 inline Vector operator+(const Vector& a,const Vector& b){return Vector(a.x+b.x,a.y+b.y);}//向量+向量=向量
 inline Vector operator-(const Point& a,const Point& b){return Vector(a.x-b.x,a.y-b.y);}//点-点=向量
 inline Vector operator*(const Vector& a,const double& p){return Vector(a.x*p,a.y*p);}//向量*实数=向量
 inline Vector operator/(const Vector& a,const double& p){return Vector(a.x/p,a.y/p);}//向量/实数=向量
 inline bool operator<( const Point& A,const Point& B ){return dcmp(A.x-B.x)<||(dcmp(A.x-B.x)==&&dcmp(A.y-B.y)<);}
 inline bool operator==(const Point&a,const Point&b){return dcmp(a.x-b.x)==&&dcmp(a.y-b.y)==;}
 inline bool operator!=(const Point&a,const Point&b){return a==b?false:true;}
 struct Segment{
     Point a,b;
     Segment(){}
     Segment(Point _a,Point _b){a=_a,b=_b;}
     inline bool friend operator<(const Segment& p,const Segment& q){return p.a<q.a||(p.a==q.a&&p.b<q.b);}
     inline bool friend operator==(const Segment& p,const Segment& q){return (p.a==q.a&&p.b==q.b)||(p.a==q.b&&p.b==q.a);}
 };
 struct Circle{
     Point c;
     double r;
     Circle(){}
     Circle(Point _c, double _r):c(_c),r(_r) {}
     Point point(double a)const{return Point(c.x+cos(a)*r,c.y+sin(a)*r);}
     bool friend operator<(const Circle& a,const Circle& b){return a.r<b.r;}
 };
 struct Line{
     Point p;
     Vector v;
     double ang;
     Line() {}
     Line(const Point &_p, const Vector &_v):p(_p),v(_v){ang = atan2(v.y, v.x);}
     inline bool operator<(const Line &L)const{return  ang < L.ang;}
 };
 inline double Dot(const Vector& a,const Vector& b){return a.x*b.x+a.y*b.y;}//|a|*|b|*cosθ 点积
 inline double Length(const Vector& a){return sqrt(Dot(a,a));}//|a| 向量长度
 inline double Angle(const Vector& a,const Vector& b){return acos(Dot(a,b)/Length(a)/Length(b));}//向量夹角θ
 inline double Cross(const Vector& a,const Vector& b){return a.x*b.y-a.y*b.x;}//叉积 向量围成的平行四边形的面积
 inline double Area2(const Point& a,const Point& b,Point c){return Cross(b-a,c-a);}//同上 参数为三个点
 inline double DegreeToRadius(const double& deg){return deg/*PI;}
 inline double GetRerotateAngle(const Vector& a,const Vector& b){//向量a顺时针旋转theta度得到向量b的方向
     double tempa=Angle(a,Vector(,));
     if(a.y<) tempa=*PI-tempa;
     double tempb=Angle(b,Vector(,));
     if(b.y<) tempb=*PI-tempb;
     if((tempa-tempb)>) return tempa-tempb;
     else return tempa-tempb+*PI;
 }
 inline double torad(const double& deg){return deg/*PI;}//角度化为弧度
 inline Vector Rotate(const Vector& a,const double& rad){//向量逆时针旋转rad弧度
     return Vector(a.x*cos(rad)-a.y*sin(rad),a.x*sin(rad)+a.y*cos(rad));
 }
 inline Vector Normal(const Vector& a){//计算单位法线
     double L=Length(a);
     return Vector(-a.y/L,a.x/L);
 }
 inline Point GetLineProjection(const Point& p,const Point& a,const Point& b){//点在直线上的投影
     Vector v=b-a;
     return a+v*(Dot(v,p-a)/Dot(v,v));
 }
 inline Point GetLineIntersection(Point p,Vector v,Point q,Vector w){//求直线交点 有唯一交点时可用
     Vector u=p-q;
     double t=Cross(w,u)/Cross(v,w);
     return p+v*t;
 }
 int ConvexHull(Point* p,int n,Point* sol){//计算凸包
     sort(p,p+n);
     int m=;
     for(int i=;i<n;i++){
         while(m>&&dcmp(Cross(sol[m-]-sol[m-],p[i]-sol[m-]))<=) m--;
         sol[m++]=p[i];
     }
     int k=m;
     for(int i=n-;i>=;i--){
         while(m>k&&dcmp(Cross(sol[m-]-sol[m-],p[i]-sol[m-]))<=) m--;
         sol[m++]=p[i];
     }
     if(n>) m--;
     return m;
 }
 double Heron(double a,double b,double c){//海伦公式
     double p=(a+b+c)/;
     return sqrt(p*(p-a)*(p-b)*(p-c));
 }
 bool SegmentProperIntersection(const Point& a1,const Point& a2,const Point& b1,const Point& b2){//线段规范相交判定
     double c1=Cross(a2-a1,b1-a1),c2=Cross(a2-a1,b2-a1);
     double c3=Cross(b2-b1,a1-b1),c4=Cross(b2-b1,a2-b1);
     return dcmp(c1)*dcmp(c2)<&&dcmp(c3)*dcmp(c4)<;
 }
 double CutConvex(const int& n,Point* poly,const Point& a,const Point& b, vector<Point> result[]){//有向直线a b 切割凸多边形
     vector<Point> points;
     Point p;
     Point p1=a,p2=b;
     int cur,pre;
     result[].clear();
     result[].clear();
     result[].clear();
     if(n==) return ;
     double tempcross;
     tempcross=Cross(p2-p1,poly[]-p1);
     if(dcmp(tempcross)==) pre=cur=;
     else if(tempcross>) pre=cur=;
     else pre=cur=;
     for(int i=;i<n;i++){
         tempcross=Cross(p2-p1,poly[(i+)%n]-p1);
         if(dcmp(tempcross)==) cur=;
         else if(tempcross>) cur=;
         else cur=;
         if(cur==pre){
             result[cur].push_back(poly[(i+)%n]);
         }
         else{
             p1=poly[i];
             p2=poly[(i+)%n];
             p=GetLineIntersection(p1,p2-p1,a,b-a);
             points.push_back(p);
             result[pre].push_back(p);
             result[cur].push_back(p);
             result[cur].push_back(poly[(i+)%n]);
             pre=cur;
         }
     }
     sort(points.begin(),points.end());
     if(points.size()<){
         return ;
     }
     else{
         return Length(points.front()-points.back());
     }
 }
 double DistanceToSegment(Point p,Segment s){//点到线段的距离
     if(s.a==s.b) return Length(p-s.a);
     Vector v1=s.b-s.a,v2=p-s.a,v3=p-s.b;
     if(dcmp(Dot(v1,v2))<) return Length(v2);
     else if(dcmp(Dot(v1,v3))>) return Length(v3);
     else return fabs(Cross(v1,v2))/Length(v1);
 }
 inline bool isPointOnSegment(const Point& p,const Segment& s){
     return dcmp(Cross(s.a-p,s.b-p))==&&dcmp(Dot(s.a-p,s.b-p))<;
 }
 int isPointInPolygon(Point p, Point* poly,int n){//点与多边形的位置关系
     int wn=;
     for(int i=;i<n;i++){
         Point& p2=poly[(i+)%n];
         if(isPointOnSegment(p,Segment(poly[i],p2))) return -;//点在边界上
         int k=dcmp(Cross(p2-poly[i],p-poly[i]));
         int d1=dcmp(poly[i].y-p.y);
         int d2=dcmp(p2.y-p.y);
         if(k>&&d1<=&&d2>)wn++;
         if(k<&&d2<=&&d1>)wn--;
     }
     if(wn) return ;//点在内部
     else return ;//点在外部
 }
 double PolygonArea(Point* p,int n){//多边形有向面积
     double area=;
     for(int i=;i<n-;i++)
         area+=Cross(p[i]-p[],p[i+]-p[]);
     return area/;
 }
 int GetLineCircleIntersection(Line L,Circle C,Point& p1,Point& p2){//圆与直线交点 返回交点个数
     double a = L.v.x, b = L.p.x - C.c.x, c = L.v.y, d = L.p.y-C.c.y;
     double e = a*a + c*c, f = *(a*b+c*d), g = b*b + d*d -C.r*C.r;
     double delta = f*f - *e*g;
     if(dcmp(delta) < )  return ;//相离
     if(dcmp(delta) == ) {//相切
         p1=p1=L.p+L.v*(-f/(*e));
         return ;
     }//相交
     p1=(L.p+L.v*(-f-sqrt(delta))/(*e));
     p2=(L.p+L.v*(-f+sqrt(delta))/(*e));
     return ;
 }
 double rotating_calipers(Point *ch,int n)//旋转卡壳
 {
     int q=;
     double ans=;
     ch[n]=ch[];
     for(int p=;p<n;p++)
     {
         while(Cross(ch[q+]-ch[p+],ch[p]-ch[p+])>Cross(ch[q]-ch[p+],ch[p]-ch[p+]))
             q=(q+)%n;
         ans=max(ans,max(Length(ch[p]-ch[q]),Length(ch[p+]-ch[q+])));
     }
     return ans;
 }
 Polygon CutPolygon(Polygon poly,const Point& a,const Point& b){//用a->b切割多边形 返回左侧
     Polygon newpoly;
     int n=poly.size();
     for(int i=;i<n;i++){
         Point c=poly[i];
         Point d=poly[(i+)%n];
         if(dcmp(Cross(b-a,c-a))>=) newpoly.push_back(c);
         if(dcmp(Cross(b-a,c-d))!=){
             Point ip=GetLineIntersection(a,b-a,c,d-c);
             if(isPointOnSegment(ip,Segment(c,d))) newpoly.push_back(ip);
         }
     }
     return newpoly;
 }
 int GetCircleCircleIntersection(Circle c1,Circle c2,Point& p1,Point& p2){//求两圆相交
     double d=Length(c1.c-c2.c);
     if(dcmp(d)==){
         if(dcmp(c1.r-c2.r)==) return -;//两圆重合
         return ;
     }
     if(dcmp(c1.r+c2.r-d)<) return ;
     if(dcmp(fabs(c1.r-c2.r)-d)>) return ;
     double a=Angle(c2.c-c1.c,Vector(,));
     double da=acos((c1.r*c1.r+d*d-c2.r*c2.r)/(*c1.r*d));
     p1=c1.point(a-da);p2=c1.point(a+da);
     if(p1==p2) return ;
     return ;
 }
 inline bool isPointOnleft(Point p,Line L){return dcmp(Cross(L.v,p-L.p))>;}//点在直线左边 线上不算
 int HalfplaneIntersection(Line *L,int n,Point* poly){//半平面交
     sort(L,L+n);
     int first,last;
     Point* p=new Point[n];
     Line* q=new Line[n];
     q[first=last=]=L[];
     for(int i=;i<n;i++){
         while(first<last&&!isPointOnleft(p[last-],L[i])) last--;
         while(first<last&&!isPointOnleft(p[first],L[i])) first++;
         q[++last]=L[i];
         if(dcmp(Cross(q[last].v,q[last-].v))==){
             last--;
             if(isPointOnleft(L[i].p,q[last])) q[last]=L[i];
         }
         if(first<last) p[last-]=GetLineIntersection(q[last-].p,q[last-].v,q[last].p,q[last].v);
     }
     while(first<last&&!isPointOnleft(p[last-],q[first])) last--;
     if(last-first<=) return ;
     p[last]=GetLineIntersection(q[last].p,q[last].v,q[first].p,q[first].v);
     int m=;
     for(int i=first;i<=last;i++) poly[m++]=p[i];
     return m;
 }
 //两点式化为一般式A = b.y-a.y, B = a.x-b.x, C = -a.y*(B)-a.x*(A);
 //--------------------------------------
 //--------------------------------------
 //--------------------------------------
 //--------------------------------------
 //--------------------------------------
 Point point[],ppoint[];
 int main()
 {
     int n,m;
     while(~scanf("%d%d",&n,&m))
     {
         int tot = ;
         double x,y,r;
         for(int i = ;i<n;i++)
         {
             scanf("%lf%lf%lf",&x,&y,&r);
             for(double j = ;j<*PI;j += 0.0032)
             {
                 point[tot++] = Point(x+r*cos(j),y+r*sin(j));
             }
         }
         for(int i = ;i<m;i++)
             for(int j = ;j<;j++)
             {
                 scanf("%lf%lf",&x,&y);
                 point[tot++] = Point(x,y);
             }
         tot=ConvexHull(point,tot,ppoint);
         double ans = ;
         Point pre = ppoint[];
         for(int i = ;i<tot;i++)
         {
             ans += Length(ppoint[i]-pre);
             pre = ppoint[i];
         }
         ans += Length(ppoint[]-pre);
         printf("%.5f\n",ans);
     }
     return ;
 }