算法提高 连接乘积

 1 import java.util.ArrayList;
 2 import java.util.Arrays;
 3 import java.util.Scanner;
 4 
 5 import java.util.*;
 6 import java.lang.Math;
 7 class Main {
 8     static char[] a = {‘1‘,‘2‘,‘3‘,‘4‘,‘5‘,‘6‘,‘7‘,‘8‘,‘9‘};
 9     public static void main(String[] args) {
10         List<String> list = new ArrayList<>();
11         for(int i=1;i<10000;i++){
12                 String s = "";
13                 int h = 1;
14                 while(s.length()<9){
15                     s = s+i*h;
16                     h++;
17                 }
18                 //System.out.println(s);
19                 if(s.length()==9&&f(s)){
20                     list.add(s);
21             }
22         }
23         Collections.sort(list);
24         for(String s:list){
25             System.out.println(s);
26         }
27     }
28     static boolean f(String s){
29         int i;
30         char[] b = s.toCharArray();
31         Arrays.sort(b);
32         for(i=0;i<s.length();i++){
33             if(b[i]!=a[i]){
34                 break;
35             }
36         }
37         if(i==s.length()){
38             return true;
39         }else{
40             return false;
41         }
42     }
43     
44 }