题解 | #提取不重复的整数#

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String line = scanner.nextLine();

        char[] charArray = line.toCharArray();

        List<String> list = new ArrayList<>();

        for (int i = charArray.length-1; i >=0 ; i--) {
            if (!list.contains(charArray[i]+""))
                list.add(charArray[i]+"");
        }

        String string = list.toString();
        System.out.println(string.substring(1, string.length()-1).replaceAll(", ",""));


    }
}