三分模板

#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
#define fo(i,a,b) for (int i=a;i<=b;i++)
#define N 50005
#define INF 2147483647
using namespace std;
struct note
{
int x,y,w;
}a
;
int n;
double ans;
inline int read()
{
int x=0,w=1;
char ch=getchar();
while(ch>'9'||ch<'0'){if(ch=='-')w=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*w;
}
double Calc1(double x)
{
double sum=0;
fo(i,1,n) sum+=a[i].w*abs(x-a[i].x);
return sum;
}
double Calc2(double y)
{
double sum=0;
fo(i,1,n) sum+=a[i].w*abs(y-a[i].y);
return sum;
}
int main()
{
n=read();
fo(i,1,n) a[i].w=read();
fo(i,1,n) a[i].x=read(),a[i].y=read();
double l=-INF,r=INF;
while (r-l>=0.00000001)
{
double mid1=(r-l)/3+l,mid2=((r-l)/3)*2+l;
if (Calc1(mid1)<Calc1(mid2)) r=mid2;
else l=mid1;
}
ans+=Calc1(l);
l=-INF,r=INF;
while (r-l>=0.00000001)
{
double mid1=(r-l)/3+l,mid2=((r-l)/3)*2+l;
if (Calc2(mid1)<Calc2(mid2)) r=mid2;
else l=mid1;
}
ans+=Calc2(l);
printf("%.0lf.00",ans);
}