打印出所有每一位都与其他位不重复的自然数

package com.zl.jvm;

import java.util.ArrayList;

public class TestSet {

    
    public static void main(String[] args) {

        //ArrayList<String> s2 = new ArrayList<>();

        char[] a = { '0', '1', '2', '3', '4','5','6','7','8','9' };
        //先插入1位不重复的排出0
        ArrayList<String> first  = new ArrayList<>();
        first.add("1");
        first.add("2");
        first.add("3");
        first.add("4");
        first.add("5");
        first.add("6");
        first.add("7");
        first.add("8");
        first.add("9");

    /*    for (int i = 0; i < a.length; i++) {
            char temp1 = a[i];

            if ('0' == temp1) {
                continue;
            }
            for (int j = 0; j < a.length; j++) {
                char temp2 = a[j];

                if (temp1 == temp2) {
                    continue;
                }

                s2.add("" + temp1 + temp2);

            }
        }*/
        
        //计算出0-9组成2位长度 每一位不重复自然数 例:12 13
        //11这种 算重复
        ArrayList<String> s = wei(first,a,2); 
        System.out.println(s.size());

    }
    
    public static ArrayList<String> wei(ArrayList<String>s,char[] a,int count) {
        
        ArrayList<String> s3 = new ArrayList<>();
        
        if(count>1) {
            count-=1;
            for (int i = 0; i < s.size(); i++) {
                StringBuilder sb = new StringBuilder();
                String temp = s.get(i);
                sb.append(temp);
                char[] chars2 = temp.toCharArray();
                for (int j = 0; j < a.length; j++) {
                    if(check(chars2,a[j])) {
                        s3.add(sb.toString() + a[j]);
                    }
                    
                }

            }
            return wei(s3,a,count);
        }
        return s;
    }
    

    //判断是否每一位和要组合的数字是否重复
    private static boolean check( char[] ch,char temp) {
        for (int z = 0; z < ch.length; z++) {
            if (ch[z] == temp) {
                return false;
            }
        }
        return true;
    }
}