题解 | #提取不重复的整数#

import java.util.LinkedHashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        LinkedHashSet<Object> linkedHashSet = new LinkedHashSet<>();
        int num = scanner.nextInt();
        String str = num + "";
        char[] chars = str.toCharArray();
        for (int i = chars.length - 1; i >= 0; i--) {
            linkedHashSet.add(chars[i]);
        }
        for (Object obj : linkedHashSet) {
            // String s = obj + "";
            // int n = Integer.parseInt(s);
            char ch = (char) obj;
            int n = ch - 48;
            System.out.print(n);
        }
    }
}