题解 | #表示数字#

import java.util.*;

// 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
        String line = in.nextLine();
        StringBuilder sb = new StringBuilder();

        if (Character.isDigit(line.charAt(0))) {
            sb.append("*");
        }

        for (int i = 0; i < line.length() - 1; i++) {
            Character first = line.charAt(i);
            sb.append(first);
            Character second = line.charAt(i + 1);
            if (Character.isDigit(first) ^ Character.isDigit(second)) {
                sb.append("*");
            }
        }
        Character last = line.charAt(line.length() - 1);
        sb.append(last);
        if (Character.isDigit(last)) {
            sb.append("*");
        }

        System.out.println(sb.toString());

    }
}