平面上给定n条线段，找出一个点，使这个点到这n条线段的距离和最小。

题目：平面上给定n条线段，找出一个点，使这个点到这n条线段的距离和最小。

源码如下：

 #include <iostream>
 #include <string.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <time.h>
 #include <math.h>  

 #define N 1005
 #define eps 1e-8     //搜索停止条件阀值
 #define INF 1e99
 #define delta 0.98   //温度下降速度
 #define T 100        //初始温度  

 using namespace std;  

 int dx[] = {, , -, };
 int dy[] = {-, , , };  //上下左右四个方向  

 struct Point
 {
     double x, y;
 };  

 Point s[N], t[N];  

 double cross(Point A, Point B, Point C)
 {
     return (B.x - A.x) * (C.y - A.y) - (B.y - A.y) * (C.x - A.x);
 }    

 double multi(Point A, Point B, Point C)
 {
     return (B.x - A.x) * (C.x - A.x) + (B.y - A.y) * (C.y - A.y);
 }    

 double dist(Point A, Point B)
 {
     return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));
 }  

 double GetDist(Point A, Point B, Point C)
 {
     if(dist(A, B) < eps) return dist(B, C);
     if(multi(A, B, C) < -eps) return dist(A, C);
     if(multi(B, A, C) < -eps) return dist(B, C);
     return fabs(cross(A, B, C) / dist(A, B));
 }    

 double GetSum(Point s[], Point t[], int n, Point o)
 {
     double ans = ;
     while(n--)
         ans += GetDist(s[n], t[n], o);
     return ans;
 }  

 double Search(Point s[], Point t[], int n, Point &o)
 {
     o = s[];
     double tem = T;
     double ans = INF;
     while(tem > eps)
     {
         bool flag = ;
         while(flag)
         {
             flag = ;
             for(int i = ; i < ; i++)    //上下左右四个方向
             {
                 Point z;
                 z.x = o.x + dx[i] * tem;
                 z.y = o.y + dy[i] * tem;
                 double tp = GetSum(s, t, n, z);
                 if(ans > tp)
                 {
                     ans = tp;
                     o = z;
                     flag = ;
                 }
             }
         }
         tem *= delta;
     }
     return ans;
 }  

 int main()
 {
     int n;
     while(scanf("%d", &n) != EOF)
     {
         for(int i = ; i < n; i++)
             scanf("%lf %lf %lf %lf", &s[i].x, &s[i].y, &t[i].x, &t[i].y);
         Point o;
         double ans = Search(s, t, n, o);
         printf("%.1lf %.1lf %.1lf\n", o.x, o.y, ans);
     }
     return ;
 }