代码如下

package Test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Scanner;

public class 吃奶酪 {
	static location loc[] = new location[100];
	static float sum =0 ;
	static int n ; 
	static ArrayList<Float> arrayList = new ArrayList<>();
	static HashSet<Integer> hashSet = new HashSet<>();
public static void main(String[] args) {
	
	Scanner scanner = new Scanner(System.in);
	n=scanner.nextInt();
	for (int i = 1; i <=n; i++) {
		int x = scanner.nextInt();
		int y = scanner.nextInt();
		location t1 = new location(x, y);
		loc[i]=t1;
	}
	dfs(0,0,n);
	float min = Collections.min(arrayList);
	System.out.printf("%.2f",min);
	hashSet.clear();
	
	
}
private static void dfs(int x, int y, int n) {
	if (hashSet.size()==n) {
		arrayList.add(sum);
		return;
		
	}
	if (n>0) {
		for (int i = 1; i <=n; i++) {
			if (!hashSet.contains(i)) {
			
				hashSet.add(i);
				int tx = loc[i].x;
				int ty = loc[i].y;

				float length = (float) Math.sqrt((tx-x)*(tx-x)+(ty-y)*(ty-y)) ;
				
				sum=sum+length;
				
				dfs(tx, ty, n);
				hashSet.remove(i);
				sum=sum-length;
			
			}
			
			
		}
	}
	
	
}
}
class location{
	int x;
	int y;
	public location(int x, int y) {
		this.x = x ;
		this.y = y ;
	}
}