题解 | #提取不重复的整数#

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

// 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);
        String nums = in.nextLine();
        LinkedHashSet<Character> distinctNums = new LinkedHashSet<>();
        for (int i = nums.length() - 1; i >= 0; i--) {
            distinctNums.add(nums.charAt(i));
        }
        for (Character distinctNum : distinctNums) {
            System.out.print(distinctNum);
        }
    }
}