poj2420A Star not a Tree?(模拟退火）

链接

求某一点到其它点距离和最小，求这个和，这个点 为费马点。

做法：模拟退火

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 100000
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 struct point
 {
     double x,y;
     point(double x=,double y =):x(x),y(y){}
 }p[N];
 int n;
 int dir[][] = {,,,-,,,-,};
 typedef point pointt;
 pointt operator -(point a,point b)
 {
     return point(a.x-b.x,a.y-b.y);
 }
 double dis(point a)
 {
     return sqrt(a.x*a.x+a.y*a.y);
 }
 double cal(point pp)
 {
     int i;
     double s = ;
     for(i = ; i <= n; i++)
     s+=dis(pp-p[i]);
     return s;
 }
 int main()
 {
     int i;
     while(scanf("%d",&n)!=EOF)
     {
         double t = ;
         point pp = point(,);
         for(i = ; i <= n;i ++)
         {
             scanf("%lf%lf",&p[i].x,&p[i].y);
             pp.x+=p[i].x;
             pp.y+=p[i].y;
         }
         pp.x /=n;
         pp.y /=n;
         double sum = cal(pp),tmp;
         point tp,ans = pp;
         while(t>0.02)
         {
             int flag = ;
             while(flag)
             {
                 flag = ;
                 for(i = ; i<  ; i++)
                 {
                     tp = point(pp.x+dir[i][]*t,pp.y+dir[i][]*t);
                     tmp = cal(tp);
                     if(tmp<sum)
                     {
                         sum = tmp;
                         flag = ;
                         ans = tp;
                     }
                 }
                 pp = ans;
             }
             t/=;
         }
         printf("%.0f\n",sum);
     }
     return ;
 }