[POJ 2420] A Star not a Tree?

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <ctime>
#include <cstdlib>
using namespace std;
#define INF 1e20
#define PI acos(-1.0)
#define N 110

struct Point
{
    double x,y;
    Point(){}
    Point(double x,double y):x(x),y(y){}
};
int n;
Point p[N];

double cal(Point t)
{
    double sum=0;
    for(int i=1;i<=n;i++) sum+=sqrt((p[i].x-t.x)*(p[i].x-t.x)+(p[i].y-t.y)*(p[i].y-t.y));
    return sum;
}
void solve()
{
    int TN=4,DN=100;
    Point u,v,ansp;
    double ud,vd,ansd=INF;
    double step=10000,eps=1e-2,r=0.85;

    while(TN--)
    {
        u=Point(rand()%10000,rand()%10000);
        ud=cal(u);
        while(step>eps)
        {
            bool flag=1;
            while(flag)
            {
                flag=0;
                for(int i=0;i<DN;i++)
                {
                    double d=2*PI*(double)rand()/RAND_MAX;
                    v.x=u.x+sin(d)*step;
                    v.y=u.y+cos(d)*step;
                    vd=cal(v);
                    if(vd<ud) ud=vd,u=v,flag=1;
                }
            }
            step*=r;
        }
        if(ud<ansd) ansd=ud,ansp=u;
    }
    printf("%.0f\n",ansd);
}
int main()
{
    //srand((int)time(NULL)); //POJ上不能用
    while(scanf("%d",&n)!=EOF)
    {
        for(int i=1;i<=n;i++) scanf("%lf%lf",&p[i].x,&p[i].y);
        solve();
    }
    return 0;
}