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);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String line = in.nextLine();
            char[] charArray = line.toCharArray();
            int[] numChars = new int[]{0, 0, 0, 0, 0, 0, 0, 0, 0};
            
            StringBuffer sb = new StringBuffer();
            for (int i = charArray.length - 1; i >= 0;i--) {
                char a = charArray[i];
                if (numChars[a - '0'-1] == 0) {
                    sb.append(a);
                    numChars[a - '0'-1]++;
                }                
            }
            System.out.println(sb.toString());
        }
    }
}