寒假训练第九场 Brocard Point of a Triangle

题意：求布洛卡点坐标

思路：直接利用布洛卡点的性质。http://pan.baidu.com/s/1eQiP76E

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<iostream>
 #include<cstdlib>
 #include<cstring>
 #include<cmath>
 #include<vector>
 #define clc(a,b) memset(a,b,sizeof(a))
 using namespace std;
 const double eps=1e-;
 const double pi=acos(-);
 const int maxn=;
 using namespace std;

 int t;
 int main()
 {
     while(~scanf("%d",&t))
     {
         while(t--)
         {
             int K;
             double c,d,a,b,e,f,m1,m2,m3,k,q;
             double x,y;
             scanf("%d%lf%lf%lf%lf%lf%lf",&K,&a,&b,&e,&f,&c,&d);
             double l1,l2,l3;
             l1=(a-e)*(a-e)+(b-f)*(b-f);
             l2=(c-e)*(c-e)+(d-f)*(d-f);
             l3=(c-a)*(c-a)+(d-b)*(d-b);
             m1=(l1*l3*l3)/(l1*l2+l2*l3+l3*l1);
             m2=(l3*l2*l2)/(l1*l2+l2*l3+l3*l1);
             m3=(l2*l1*l1)/(l1*l2+l2*l3+l3*l1);
             if(a!=c&&b!=d)
             {
                 k=(-a+e)/(-a+c);
                 q=(-b+f)/(-b+d);
                 x=(e*e-b*b+(-q)*m1-m3+q*m2+q*(b*b-c*c)+f*f-a*a+q*(a*a-d*d))/(*q*a-*q*c-*a+*e);
                 y=(e*e-b*b+m1*(-k)-m3+k*m2+k*(b*b-c*c)-a*a+f*f+k*(a*a-d*d))/(*k*b-*k*d-*b+*f);
                 printf("%d %.5f %.5f\n",K,x,y);
             }
             else if(a==c)
             {
                 y=(m1-m2+d*d-b*b)/(-*b+*d);
                 x=a+sqrt(m1-(y-b)*(y-b));
                 printf("%d %.5f %.5f\n",K,x,y);
             }
             else
             {
                 x=(m1-m2+c*c-a*a)/(-*a+*c);
                 y=b+sqrt(m1-(x-a)*(x-a));
                 printf("%d %.5f %.5f\n",K,x,y);
             }
         }
     }
     return ;
 }