我朋友的写法，AC了，留在ide里，就是排列组合吧。 public class lovely {     static double[][] arr=new double[6][2];     static double [] []dis=new double[6][6];     public static void main(String[] args) {         double distance=0;                 Scanner sc = new Scanner(System.in);             for(int i=1;i<=5;i++) {             for(int j=0;j<2;j++)arr[i][j]=sc.nextInt();                      }         for(int i=0;i<6;i++) {             for(int j=0;j<6;j++) {                 dis[i][j]=Math.sqrt(Math.abs(arr[i][0]-arr[j][0])*Math.abs(arr[i][0]-arr[j][0])+Math.abs(arr[i][1]-arr[j][1])*Math.abs(arr[i][1]-arr[j][1]));             }         }         ArrayList<Integer> save=new <Integer>ArrayList();                 save.add(1);         save.add(2);         save.add(3);         save.add(4);         save.add(5);         distance=showin(0,save);                  System.out.println((int)distance);     }          public static double showin(Integer b,ArrayList<Integer> save) {         Iterator<Integer> it = save.iterator();         double max=80000000;         if(!it.hasNext())return 0;         if(save.size()==1) {                         Integer i=it.next();             return dis[0][i]+dis[b][i];                     }         while (it.hasNext()) {             Integer a=it.next();                          ArrayList<Integer> newsave=new <Integer>ArrayList();             newsave.addAll(save);               newsave.remove(a);             Double c=showin(a, newsave);             if(max>dis[b][a]+c)max=dis[b][a]+c;                                   }         return max;     }      }