题解 | #提取不重复的整数#

import java.util.Scanner; 

import java.util.Set;
import java.util.HashSet;

// 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);
        Set<String> set = new HashSet<String>();
        String num = in.next();
        String[] nums = num.split("");
        for(String s : nums){
            set.add(s);
        }
        String temp = "";
        for(int i = nums.length-1; i>=0; i--){
            if(set.contains(nums[i])){
                set.remove(nums[i]);
                temp = temp + nums[i];
            }
            
        }
        System.out.println(temp);
    }
}