题解 | #提取不重复的整数#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String line = in.nextLine();
        boolean[] arr = new boolean[10];
        for (int i = line.length() - 1; i >= 0; i--) {
            int num = Integer.parseInt(String.valueOf(line.charAt(i)));
            if(!arr[num]){
                arr[num]=true;
                System.out.print(num);
            }
        }
    }
}