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-8;
const double pi=acos(-1);
const int maxn=1000010;
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+(1-q)*m1-m3+q*m2+q*(b*b-c*c)+f*f-a*a+q*(a*a-d*d))/(2*q*a-2*q*c-2*a+2*e);
                y=(e*e-b*b+m1*(1-k)-m3+k*m2+k*(b*b-c*c)-a*a+f*f+k*(a*a-d*d))/(2*k*b-2*k*d-2*b+2*f);
                printf("%d %.5f %.5f
",K,x,y);
            }
            else if(a==c)
            {
                y=(m1-m2+d*d-b*b)/(-2*b+2*d);
                x=a+sqrt(m1-(y-b)*(y-b));
                printf("%d %.5f %.5f
",K,x,y);
            }
            else
            {
                x=(m1-m2+c*c-a*a)/(-2*a+2*c);
                y=b+sqrt(m1-(x-a)*(x-a));
                printf("%d %.5f %.5f
",K,x,y);
            }
        }
    }
    return 0;
}