题解 | #提取不重复的整数#

import java.util.*;

public class Main {

public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String [] strArray = sc.nextLine().split("");
    int len = strArray.length;
    StringBuilder sb = new StringBuilder();
    Map<String,String> map = new HashMap();
    for(int i=len-1;i>=0;i--){
        if(map.containsKey(strArray[i])){
            continue;
        }
        map.put(strArray[i],"1");
        sb.append(strArray[i]);
    }
    System.out.println(sb.toString());
  }

}