题解 | #表示数字#

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
        String str = in.nextLine();
        char[] chars = str.toCharArray();
        int cnt = 0;
        for(char cur : chars){
            if(Character.isDigit(cur)){
                cnt++;
            }
        }
        int index = 0;
        int nIndex = 0;
        char[] newChars = new char[chars.length + 2*cnt];
        while(index < chars.length){
            int begin = index;
            while(index < chars.length && Character.isDigit(chars[index])){
                index++;
            }
            if(index != begin){
                newChars[nIndex++] = '*';
                for(int i=begin;i<index;i++){
                    newChars[nIndex++] = chars[i];
                }
                newChars[nIndex++] = '*';
            }else{
                newChars[nIndex++] = chars[index++];
            }
        }
        String res = new String(newChars);
        System.out.println(res.substring(0, nIndex));
    }
}