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 in = new Scanner(System.in);
        String a = in.nextLine();
        char[] cha = a.toCharArray();
        int length = a.length();
        for(int i=0; i<a.length() / 2; i++) {
            char tem = cha[i];
            cha[i] = cha[length - i - 1];
            cha[length - i - 1] = tem;
        }
        String newArr = new String(cha);
        StringBuffer sb = new StringBuffer().append(cha[0]);
        for(int i = 1; i < length; i++) {
            if(newArr.indexOf(cha[i]) >= i) {
                sb.append(cha[i]);
            }
        }
        System.out.println(sb);
    }
}