题解 | #提取不重复的整数#

使用函数Map进行去重操作

import java.util.*;
public class Main{
    public static void main(String [] args){
        getNum();
    }

    public static void getNum(){
        Scanner scan = new Scanner(System.in);
        String input = scan.nextLine();
        Map<String,String> map = new HashMap<>();
        String ret = "";
        for(int i = input.length()-1; i >= 0; i--){
            String temp = input.charAt(i) + "";
            if(null == map || null == map.get(temp)){
                map.put(temp,temp);
                ret += temp;
            }
        }
        System.out.print(ret);
    }

}