看的蓝书的板子，Line不知道什么意思，卡了一个小时，最后在前面找到了p是点，v是向量，写了整场比赛，思路就是求出所有的点，然后求距离
#include <iostream> #include <cstring> #include <algorithm> #include <cstdio> #include <cmath> #include <vector> using namespace std; struct Point { double x,y; Point(double xx=0,double yy=0):x(xx),y(yy) {} }; typedef Point Vector; const double eps=1e-6; 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); } int dcmp(double x) { if(fabs(x)<eps) return 0; else return x<0?-1:1; } 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 Length(Vector A) { return sqrt(Dot(A,A)); } double Cross(Vector A,Vector B) { return A.x*B.y-A.y*B.x; } double distoline(Point P,Point A,Point B) { Vector v1=B-A,v2=P-A; return fabs(Cross(v1,v2))/Length(v1); } struct Circle { Point c; double r; Circle(Point c,double r):c(c),r(r) {} Point point(double a) { return Point(c.x+cos(a)*r,c.y+sin(a)*r); } }; struct Line { Point v,p; Line(Point v,Point p):v(v),p(p) {} Point point(double t) { Point zz=p+v*t; return zz; } }; Circle circleout(Point p1,Point p2,Point p3) { double Bx=p2.x-p1.x,By=p2.y-p1.y; double Cx=p3.x-p1.x,Cy=p3.y-p1.y; double D=2*(Bx*Cy-By*Cx); double cx=(Cy*(Bx*Bx+By*By) - By*(Cx*Cx+Cy*Cy))/D+p1.x; double cy=(Bx*(Cx*Cx+Cy*Cy) - Cx*(Bx*Bx+By*By))/D+p1.y; Point p=Point(cx,cy); return Circle(p,Length(p1-p)); } Circle circleint(Point p1,Point p2,Point p3) { double a=Length(p2-p3); double b=Length(p3-p1); double c=Length(p1-p2); Point p=(p1*a+p2*b+p3*c)/(a+b+c); return Circle(p,distoline(p,p1,p2)); } int getlinejiaocircle(Line L,Circle C,double &t1,double &t2,vector<Point> &sol) { 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=2*(a*b+c*d), g=b*b+d*d-C.r*C.r; double delta=f*f-4*e*g; if(dcmp(delta)<0) return 0; if(dcmp(delta)==0) { t1=t2=-f/(2*e); sol.push_back(L.point(t1)); return 1; } t1=(-f-sqrt(delta))/(2*e); sol.push_back(L.point(t1)); t2=(-f+sqrt(delta))/(2*e); sol.push_back(L.point(t2)); return 2; } Point gettwolinejiao(Point P,Vector v,Point Q,Vector w) { Vector u=P-Q; double t=Cross(w,u)/Cross(v,w); return P+v*t; } int t; int main() { scanf("%d",&t); while(t--) { int Case; scanf("%d",&Case); double bx,cx,cy; scanf("%lf%lf%lf",&bx,&cx,&cy); Point A=Point(0,0),B=Point(bx,0),C=Point(cx,cy); Circle I=circleint(A,B,C); Circle O=circleout(A,B,C); double t1=0,t2=0; vector<Point> sol; Point ii=I.c; sol.clear(); Line bi=Line(ii-B,B); int nn=getlinejiaocircle(bi,O,t1,t2,sol); Point N; if(sol[0]==B) N=sol[1]; else N=sol[0]; sol.clear(); Line ai=Line(ii-A,A); nn=getlinejiaocircle(ai,O,t1,t2,sol); Point M; if(sol[0]==A) M=sol[1]; else M=sol[0]; sol.clear(); Line ci=Line(ii-C,C); nn=getlinejiaocircle(ci,O,t1,t2,sol); Point P; if(sol[0]==C) P=sol[1]; else P=sol[0]; Vector AC=C-A; Vector NP=P-N; Point F=gettwolinejiao(A,AC,N,NP); Vector AB=B-A; Point E=gettwolinejiao(A,AB,N,NP); double ef=Length(E-F); Vector NM=M-N; Point G=gettwolinejiao(A,AC,N,NM); double fg=Length(G-F); Vector PM=M-P; Point K=gettwolinejiao(A,AB,P,PM); double ek=Length(E-K); Vector BC=C-B; Point J=gettwolinejiao(B,BC,P,PM); double kj=Length(J-K); Point H=gettwolinejiao(N,NM,B,BC); double gh=Length(H-G); double hj=Length(J-H); double ans=ef+fg+ek+kj+gh+hj; printf("%d ",Case); printf("%.4f ",ef); printf("%.4f ",fg); printf("%.4f ",gh); printf("%.4f ",hj); printf("%.4f ",kj); printf("%.4f\n",ek); } return 0; }
转载于:https://www.cnblogs.com/Wangwanxiang/p/9502736.html
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