题解 | #提取不重复的整数#

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String[] strs = scan.nextLine().trim().split("");
        int[] acc = new int[10];
        StringBuffer sb = new StringBuffer("");
        for (int i = strs.length - 1; i > -1; i--) {
            int num = ++acc[Integer.valueOf(strs[i])];
            if (num <= 1) {
                sb.append(strs[i]);
            }
        }
        System.out.println(sb);
    }
}