学步园

#include<iostream>
#include<cstdio>
#include<cmath>
#define inf 0x7fffffff
using namespace std;
inline int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
struct point{
	double x,y,v;
}p[1001];
int n;
double xx,yy,ans,t;
inline double dis(double x,double y,point p){
	return sqrt((p.x-x)*(p.x-x)+(p.y-y)*(p.y-y));
}
inline double getsum(double x,double y){
	double res=0;
	for(int i=1;i<=n;i++)
		res+=p[i].v*dis(x,y,p[i]);
	return res;
}
int main(){
	scanf("%d",&n);
	t=10000;
	for(int i=1;i<=n;i++){
		scanf("%lf%lf%lf",&p[i].x,&p[i].y,&p[i].v);
		xx+=p[i].v*p[i].x;yy+=p[i].v*p[i].y;
	}
	xx/=n;yy/=n;
	ans=getsum(xx,yy);
	double x,y,tmp;
	while(t>0.0000001){
		x=y=0;
		for(int i=1;i<=n;i++){
			x+=p[i].v*(p[i].x-xx)/dis(xx,yy,p[i]);
			y+=p[i].v*(p[i].y-yy)/dis(xx,yy,p[i]);
		}
		tmp=getsum(xx+x*t,yy+y*t);
		if(tmp<ans){ans=tmp;xx+=x*t;yy+=y*t;}
		t*=0.9;
	}
	printf("%.2lf %.2lf\n",xx,yy);
}