题解 | 提取不重复的整数

import java.util.Scanner;

import java.util.Set;
import java.util.HashSet;
import java.util.List;
import java.util.ArrayList;

// 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);
        char[] c =  in.nextLine().toCharArray();
        List<Character> list = new ArrayList(c.length);
        for (int i = c.length - 1; i >= 0; i--) {
            if(!list.contains(c[i])){
                list.add((c[i]));
            }
        }
        
        for(Character t : list){
            System.out.print(t);
        }
        
    }
}