题解 | #提取不重复的整数#

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 sc = new Scanner(System.in);
        while (sc.hasNext()){
            String str = sc.nextLine();
            StringBuffer sb = new StringBuffer();
            String next = str.substring(str.length()-1,str.length());
            sb.append(next);
            for (int i = str.length(); i >0 ; i--) {
                if (!sb.toString().contains(str.substring(i-1,i))){
                    sb.append(str.substring(i-1,i));
                }
            }
            System.out.println(sb.toString());
        }
    }
}