MLE求调

#include <bits/stdc++.h>
using namespace std;
#define int long long
const double INF = 1e18;
int x[155];
int y[155];
int fa[155];
double d[155][155];
double r[155];
double dis(int i,int j)
{
	return sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
}
int find(int x)
{
	if(fa[x]!=x) return fa[x] = find(x);
	return x;
}
signed main()
{
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n;
	cin>>n;
	for(int i=1;i<=n;i++) 
	{
		cin>>x[i]>>y[i];
		fa[i] = i;
	}
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			char c;
			cin>>c;
			if(c-'0') 
			{
				d[i][j] = dis(i,j);
				if(find(i)!=find(j)) fa[j] = i;
			}
			else d[i][j] = INF;
		}
	}
	for(int k=1;k<=n;k++)
	{
		for(int i=1;i<=n;i++)
		{
			for(int j=1;j<=n;j++)
				d[i][j] = min(d[i][j],d[i][k]+d[k][j]);
		}
	}
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++) 
		{
			if(d[i][j]<INF)
				r[i] = max(r[i],d[i][j]);
		}
	}
	double ans = INF;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			if(find(i)!=find(j))
			{
				ans = min(ans,r[fa[i]]+r[fa[j]]+dis(i,j));
			}
		}
	}
	printf("%.6lf",ans);
	return 0;
}