题解 | #提取不重复的整数#

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            String str = scanner.nextLine();
            //利用LinkedHashSet无序且唯一的特性
            HashSet<Integer> hashSet = new LinkedHashSet<>();
            //利用字符串从右边往左依次向hashSet中添加
            for(int i = str.length()-1; i>=0; i--){
                hashSet.add(Integer.parseInt(
                    new String(new char[]{str.charAt(i)})
                ));
            }
            //迭代器打印
            Iterator iterator = hashSet.iterator();
            while(iterator.hasNext()){
                System.out.print(iterator.next());
            }
        }
    }
}