题解 | #提取不重复的整数#

import java.util.HashSet;
import java.util.Iterator;
import java.util.Scanner;
import java.util.Set;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int num1 = in.nextInt();
        Set<Integer> set = new HashSet<>();
        while (num1 != 0) {
           if(set.add(num1 % 10)) System.out.print(num1%10);
            num1 /= 10;
        }
    }
}