滴滴后端8.21第一题

n=abc+acc，a是1-9，b与c是0-9，a b c互不相等，100<n<2000，输出abc  
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n = sc.nextInt();
        int count=0;
        ArrayList<Integer> arr = new ArrayList<>();
        for (int i = 100; i < n; i++) {
            for (int j = i; j < n; j++) {
                if (i+j==n){
                    String str1=String.valueOf(i);
                    String str2=String.valueOf(j);
                    char[] chars1 = str1.toCharArray();
                    char[] chars2 = str2.toCharArray();
                    if (chars1.length==3 && chars2.length==3){
                        if (chars1[0]!=chars1[1] & chars1[1]!=chars1[2] & chars1[0]!=chars1[2] & chars1[0]==chars2[0] & chars1[2]==chars2[2] & chars2[2]==chars2[1]){
                            count+=1;
                            arr.add(i);
                        }
                    }

                }
            }
        }
        Collections.sort(arr);
        System.out.println(count);
        for (int i = 0; i <arr.size() ; i++) {
            if (i==arr.size()-1){
                System.out.print(arr.get(i));
            }
            else{
                System.out.print(arr.get(i)+" ");
            }
        }

    }

}