题解 | #提取不重复的整数#

查重复有现成的方法indexOf，找得到就返回下标，找不到就返回-1

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        StringBuffer buffer = new StringBuffer();
        for(int i = str.length(); i >= 1; i--){
            String s = str.substring(i - 1, i);
            if(buffer.indexOf(s) == -1){
                buffer.append(s);
            }
        }
        System.out.println(Integer.parseInt(new String(buffer)));
    }
}